The typology of internal and external structure was first presented by Jan Sultan in the Notes on S.I. 86/1. It has been implemented in the practice of some Rolfers in various forms and has shown to help understanding structure better and therefore formulating goals for working in a structurally more pertinent manner. Its potential has not even nearly been realized so far. This paper attempts to elucidate further the premises and assumptions underlying the system as well as to point out the steps which lead from a functional phenomenon to a structural typology. This should put the system on firmer theoretical ground and so aid its further development. Some implications are drawn and spelled out which may contribute to pointing out the directions in which the concept might evolve, rendering it even more applicable and relevant.

The typology is derived from the functional phenomenon of craniosacral motion which forms the subject matter of the field of craniosacral therapy (CST)(1). This motion is on a very small scale and requires a special palpation technique to be sensed. It is continuous throughout life and cyclic, at a normal frequency of 6-12/ min. In its “flexion phase” the skull rounds off- it widens primarily -, the spine extends, the front of the body goes wide, and the extremities rotate externally. “External rotation” corresponds to “flexion phase”. In the “extension phase” the skull becomes narrower and long, the spine goes deeper into its curves, the front of the body is narrower – the body becomes “deeper” -, and the extremities rotate internally. “Internal rotation” corresponds to “extension phase”.

The terms “flexion” and “extension” refer to the behaviour of the spheno-basilar junction which plays – or historically played – an important role in osteopathy of which CST is a branch. The angle at the inferior surface of the spheno-basilar synchondrosis is less than 180° and decreases further in “flexion”. It approaches 180° in “extension”.

Upledger hypothesizes in his “Pressurestat model” that the motion is driven by cyclic changes in the pressure of the liquor cerebrospinalis within the dural sack. This forms a “semi-closed hydrostatic system” containing and enclosing the brain and the spinal cord. Upledger postulates that the liquor resorption rate is constant but lower than the liquor secretion rate. This results in an increase of liquor volume which is quickly followed by an increase in pressure because liquids are practically non-compressible. This tenses the dural sack, the wall of the system, and this is thought to activate tension receptors especially in the area of the cranial sutures. They stop liquor secretion – as a negative feed-back mechanism -, and volume and pressure decrease as a consequence. The system is then ready to begin a new and identical cycle.

The “engine”, the primary unit from which the motion originates, is the liquor cerebrospinalis, including the tissue of the central nervous system. The effect of the pressure is on the dura first which encloses and locks off the liquor compartment. In accordance with geometrical principles pertaining to the relationship of surface and volume, the increasing volume and pressure transform the dura of the skull in the direction of a sphere and extend and straighten the curved dural tube in the spinal canal. The effect is practically synchronous in all parts of the liquor compartment because pressure travels almost instantaneously in closed hydrostatic systems.

The forces which drive the cycle of craniosacral motion are asymmetrical. Flexion is caused by the rising pressure inside the dural sack. The body is opened from inside. This force from inside has to overcome several kinds of resistance besides the inertia of mass in general: elastic resistance from stretched fascia including the dura, the overall tonus of the musculature which compresses the body, gravity and atmospheric pressure. These forces combine to slow down the flexion motion with increasing resistance and halt it eventually. They are then also responsible for bringing the system back to extension, compressing the dural compartment from outside. The feed-back mechanism postulated by Upledger affects the system in a parallel manner. It is physiological in nature however and in principle independent from the mechanical forces acting from outside.

Normal movement means for CST(1) that craniosacral motion be wide, smooth, and symmetrical all through the body. In practice it focuses on obstructions to such normal motion and attempts to relieve them. Upledger lists two types of restrictions: ossary and fascial. The first is not interesting to the structural point of view(2) because it doesn’t play a role in integrated bodies. Except for cases with severe pathology, bones detach from each other in normal movement – the joints open -, and so ossary restrictions don’t come into play. The second raises interest of course. But Rolfing doesn’t have much to contribute to it because of the low level of the development of its theory.

The form normal craniosacral motion takes deserves attention. The problem of determining a norm for it has two components if the bones are accepted as relevant markers. The normal axes of rotation between all the bones have to be decided on, and the directions the bones take which belong to the flexion and extension phase need to be found. The first is done by CST in the tradition of osteopathy by examining in detail the geometrical properties of the joint surfaces. This is certainly justified and successful in the case of the cranial sutures. It is somewhat less convincing for the joints of the rest of the body. One reservation – which could be said to refer to the completeness of the theory of CST – comes from the fact that the majority of these joints permit movement around more than one axis. The femur e.g. cannot only rotate in the hip joint but also adduct and abduct, flex and extend. Perhaps further refinement of the theory of CST will lead to a more complete description of motion around all axes of rotation any joint possesses. A more systematic shadow of doubt is thrown on the osteopathic method by the fact that the amplitude of the motion is minute. On its extremely small order of magnitude it would seem that almost any kind of motion could occur which is not prohibited categorically by general anatomy and enforced rigorously in the flesh.

The osteopathic concept of the joint is in stark contrast to that of Structural Integration. From the Rolfing point of view – and still starting with bones -, the first important fact which impresses itself is realizing that bones are not joined together by any firm and rigid material. There are no nuts and bolts and screws. This is always something of a surprise to laypersons, if they let the fact sink in, and results in them being lost in understanding how such a thing can function. Even when one has studied the field to some extent, realizing this fact fully and clearly is always irritating again. It seems that the image of the body as a machine is much more deeply rooted than one would think. But not only are the bones not “bolted together” as in most technical joints ? the door hinge, scissors, the wheel to the axle -, they don’t even touch. And even if cartilage is subsumed under “rigid” and considered as bone, there always exists a film of synovial fluid or a layer of connective tissue containing collagen fibers and water which separates the bones and prevents their physical contact.

A joint has two properties. It permits movement between the parts making it up, and it assures that they stay connected and centered, even under load. The problem is tricky technically, if a model joint is to be constructed using the parts nature provides. For, stability impairs mobility, and mobility jeopardizes stability.

Attempting to draw up such a model joint starting with bones, two wooden sticks or metal bars can be imagined which meet at their ends. To make matters difficult for the traditional point of view, the joint surfaces should both be slightly convex. Securing aids like discs and intraarticular ligaments are disallowed. Such a “joint” would permit movement around all three axes. Otherwise, it would do nearly everything to not make it look like a joint: its “joint surfaces” would tend all by themselves to shear apart and become dislodged. To secure this joint and still retain mobility, a tightly fitting but resilient rubber tube would be pulled over both “bones”. To safeguard against axial displacement, it could be fixed to the “bone shafts”; the tube would blend with the periostium except for the parts representing the joint capsule. The empty space inside the joint would be filled with water.

Such a model would fit the prerequisites for a joint nicely, it might even bear a little weight(3). And it would be composed entirely by parts provided by nature. It could be made more sophisticated by using several layers of rubber tubes, which correspond to fasciae of course. Paddings could be inserted between them – muscle tissue, fat and loose connective tissue, bursae – which would shape the three-dimensional properties of the joint more vividly. More rigid threads could be woven into the tubes, representing tendons and ligaments, which would narrow down the range of movements to those desired and secure the joint further against slipping.

This “rubber tube model” of the joint presents a structural alternative to the conventional way of looking at joints. Its relevance should not be underestimated. For one, analysis of joint surfaces has not even come in yet! They hardly have any importance. But it also points to some other properties which belong to the structural view point. The model shows that a joint has a neutral point. If it is thought to be suspended in the gravity field, this neutral point can be postulated to be normal if the midlines of both bones are on one vertical axis. If the lower bone is moved, and when this disturbance has ceased again, the system will swing back to its neutral point again all by itself, without involving muscle action. This is due to gravity, but the geometry of passive tension in the rubber tube also plays a role. If the system is imagined to float under water, it will also go back to neutral after having been disturbed. In this case it is solely the elastic energy stored on the extension side of the rubber tube which will effect the return. The system is self-regulating in a purely mechanical sense. Fascia alone brings the system back to home.

With the model suspended in the gravity field vertically at its neutral point, another consequence emerges. This “normal” model is characterized by balanced passive tissue tension. Any muscle activity will distort this structurally normal arrangement and damage it, at the cost of only effort. The system will return to normal all by itself – by virtue of its balanced passive tension and gravity – if and when muscles relax.

“Random” structure would be represented by the system not hanging vertically but the lower bone sticking out sideways and the upper adapting accordingly. Tension would not be balanced. In the absence of muscle activity this would be entirely due to rigidity, “shortness”, somewhere in the rubber tube. A Rolfer would find this shortness, relieve it, and so bring the system toward normal. The example illustrates that Rolfing is not primarily about releasing shortness but assessing the geometry of the structural system, deducing from this where there must be shortness in the fascial network, and releasing it in the service of normalizing the system in a geometrical sense.

To sum up the argument, the concept of joints is of negligible importance to Rolfing beyond realizing that they exist and perhaps possessing a rough notion of which one or more of the possible three axes of rotation they are designed to permit. The primary concept is that of hinges (Notes on S.I. 88/1, p. 31). A Rolfer needs to be familiar with basic geometry and have a certain facility in applying its principles to observation. For working effectively, a very good knowledge of the fascial network is necessary.

The second question, why the parts of the body move in the direction they do in flexion and extension, cannot be answered by examining joints. A leg could also rotate internally in flexion, but all the legs always seem to rotate externally in this phase. The direction the parts of the body take in flexion and extension is uniformly the same. This suggests that there exists a structural design which is identical for everybody. It manifests in the fact that when the primary unit of craniosacral motion goes into flexion or extension, the movement spreads through everybody the same way. There are no alternatives or different types of movement but only disturbances, restrictions, and modifications of one and the same normal motion.

The structural design means primarily the design of the fascial network in the Rolf sense. The rising pressure in the liquor acts on fascia in the form of the dura first and moves it. It transmits the movement along fascial connections throughout the body. There are bones interspersed sometimes, so the sequence is movement of fascia (dura), which moves bones, which move fascia. Upledger emphasizes the role of the dura as fascia and also accentuates the importance of such structures crossing the dural sack, especially the falx cerebri and tentorium cerebelli. Otherwise, the bony attachments of the dural envelope, where fascia moves bone, are of great importance. Outside the cranium the dural tube in the spinal canal is of special interest to Rolfing because it seems of primary importance for the movement of the whole body. The dural tube floats relatively freely and has bony attachments only to the circumference of the foramen magnum, the posterior walls of the vertebral bodies of C2 and C3, and of S2, and to the dorsal side of the coccyx via the filum terminale.

In the flexion phase, the rising pressure in the liquor compartment straightens out the dural tube which so accommodates the increased volume. It takes along the spine which lengthens and extends. More exactly and within the framework of structural language: the relatively tightly packed posterior wall of the trunk is straightened and lengthened from inside. The spine is an indicator for what happens with the back and is taken along by the soft tissue. This lengthening movement is eccentric because dural tube, the spine, and the back are posterior to the midline of the body. The sides and via them the front of the trunk are taken along, and so are the extremities eventually. The form of their movement, induced by the back, depends on the way they are connected to the back, on the geometrical and tensional properties of the fascial network.

The structural view is extremely demanding for the human capacity for imagination. It is almost impossible and perhaps senseless to visualize a structural body without bones. If a compromise is admitted, bones can be left in as spacers. But the joint surfaces of all the bones should be imagined as non-specific, similar to the “biconvex joint” used in the rubber-tube model of the joint. Then all joints permit all kinds of movement. Still, such a structure could not behave differently in the two phases of craniosacral motion than real bodies do. The movement would be the same, regardless of whether specific joints are present or left out. This is at least true for integrated bodies where joints open in movement and bony properties don’t get a chance to interact and guide or deviate movement.

From the structural view point, the joints as they are defined by their joint surfaces have simply adapted to the movement flowing through as dictated by the fascial net. They make it easier for fascia to transmit movement. If movement, the change of shape of the body, is primary, it is determined by the configuration and properties of the fascial net and the joints fit this. Traditionally, it is the joints which determine the shape of movement, assuming tacitly that fascia fits it. Both views are possible and it cannot be decided that one is true and the other false. They simply define different fields as a consequence which develop entirely different frameworks of reference(4).

The situation shall be illustrated by examining the knee. Structurally it is determined by the relationship of thigh and lower leg, traditionally by that of femur and tibia. The view points are completely different. Structurally, the system is sufficiently described by analyzing the spatial relationship of the gravity centers of thigh and lower leg and the rotational axis of the knee – which should have hinge function – in various postures and movements. The relative economy of these must be regarded to distil out the true structural state from the structural/functional whole. This in turn involves the rest of the body which greatly influences the situation. The knee is a mobile section of the body where the weight of what is above is carried or distributed by what’s under it.

This “language” is highly abstract although of eminent practical value. Limiting the view to the leg, it can be made a little more explicit. The gravity centers of the segments in question are extended to the “line”. Such segmental midlines are gravity lines; they can be thought to consist of an infinite number of gravity centers which belong to very thin horizontal slices in the form of disks. The midlines should be straight, in which case they signal intrasegmental order. They are quite independent of the form and position of the bones inside the flesh but represent very accurately the distribution of the mass of the segment in space.

Intersegmentally, a first structural postulate is that the midlines of thigh and lower leg should run smoothly into each other; there should be no break. If the midline of the thigh ends more medial distally and the midline of the lower leg starts out more lateral at its upper end, the lower leg can be said to be shifted lateral with respect to the thigh. A lateral or medial and anterior or posterior shift of the lower leg can so be analyzed. Secondly, the angle of the midlines at the knee can be determined. Ideally, it should be 180°, the two midlines should form one straight line. In addition, this line should be vertical in standing. If the midline of the thigh is taken as vertical, that of the lower leg can deviate laterally or medially, representing abduction and abduction, or anteriorly or posteriorly, indicating extension and flexion. The third possibility, rotation proper around the vertical axis, is not indicated by the midlines. It can be determined by analyzing the front and back sides, or the lateral and medial sides of thigh and lower leg. They should lie in planes with identical orientation. In practice the rotation around the vertical axis of hip, knee, and ankle hinge will help diagnosing segmental rotation.

This description is highly useful and well defined in the structural field. It doesn’t make sense in other fields, however, with the exception of flexion and extension, which poses a problem all of its own. To state that a lower leg – not the tibia! – abducts, or is abducted, and is shifted medially, is meaningless if one doesn’t possess the concept of midline and hinges. It is not a physiological possibility although very much a structural reality. The knee can only flex and extend, and so the tibia(!) and with it the lower leg can only be flexed or extended more or less. This belief is often held as “self-evident” although it is supported only vaguely by articular considerations. The tibial plateau is so unspecific, and the femoral epicondyles so versatile, that it can’t be seen why the femur shouldn’t slide around some on the tibia. It does, when the ligamenta cruciata are ruptured. Similarly, the femur seems to be free to rotate on the tibia. It does in strong flexion. And it can even be imagined that there could be some abduction or abduction because one epicondyle would still be centered on the tibia.

An important methodological problem is hidden in this description. It is an entirely different matter to recognize structural aberrations which are non-physiological functionally and to decide on the structural state along the path of normal movement. The first are aberrations which permit very little functional variation. Moreover, the body tends to limit them by fortifying its fascial network. In bow legs e.g., the lower leg is adducted relative to the thigh and sometimes it is also shifted laterally. Gravity augments this and tends to push the lower leg more into the aberration. Fascia will rigidify and freeze to save the structure from further collapse. The aberration becomes so fixed and appears as constant in all postures and movements. In contrast to this, flexion and extension will be “kept open”; the connective tissue with its tendency to shorten will always be widened again in the physiological dimension of movement. As a metaphor, the connective tissue resembles a jungle which tends to overgrow everything. Paths or aisles which exist in it will be kept open by use and reinforced while the jungle around them tends to grow denser and thicker. Whether a knee is structurally flexed, and how much, or extended, or hyperextended, cannot be found out by simply looking. It may be anywhere along the flexion/ extension dimension depending on the overall posture or the kind of movement chosen. The concept of the structural point on the postural curve is helpful for structural analysis. As a consequence, non-physiological aberrations can be diagnosed locally. To determine the structural state along the lines of function, the whole system must be regarded.

All this does not explain why craniosacral motion travels through the body the way it does. But a general consideration is that it will travel through the “aisles in the jungle”, choosing the path of least resistance. It will tend to adhere to the range of physiological motion. In the articular view, the general form of movement will not cause discussion. In the more restrictive and formal context of Structural Integration, hinges instead of joints will be considered, and the exact trajectory of segmental centers of gravity and segmental midlines will be in question. They should move in straight planes, and the joints should have hinge function. This means that physiological movement is generally not normal, too. But the nature of its aberration is different from that of the non-physiological kind. In practice, Rolfing will examine craniosacral motion as if the structure were absolutely normal concerning non-physiological aberrations as well as the geometry of physiological movement. This leaves open the variable of the structural point along these functionally normal lines.

Typologies can probably also be based on non-physiological aberrations because these must also be suspected to be related through the body and show a systematic pattern. At least two such typologies seem to be developing although their outlines are hazy yet. The internal/ external system orders body types along functional lines, movement through the “aisles” of the connective tissue.

It is supported by examination of normal breathing (Notes on S.I. 88/1). As far as the theory goes, it also begins with a lengthening of the back. It is of course driven by a shifting in the tonus pattern of musculature and initially marked by a tonus reduction of extrinsic musculature, especially the prevertebral one. If this movement of the back is allowed to spread through the body with minimal effort, it is found that it is identical in form with craniosacral motion. Arms and legs also want to rotate externally in inhalation because of the nature of the fascial net. They are prevented from doing so functionally, by an additional relaxation of muscles which rotate externally, or more exactly: which hinder the tissue in back of the girdles where they attach to the trunk to go maximally wide. The reason for this is the postulate of maintaining balance optimally. If breathing originates in the back and is left to travel through the body passively, balance will be upset. That the disturbance is compensated is natural because breathing is a muscular activity, controlled by neuronal patterns. Craniosacral motion does not involve the musculature at all. And it is probably because of its minute amplitude that the body does not sense a need for compensation in order to preserve balance.

The important implication is that craniosacral motion disturbs balance, although perhaps only subliminally. If exaggerated, it does so noticeably. As a consequence, both internal and external structures are not normal. Furthermore, in the flexion or extension phase balance is disturbed in two entirely and distinctly different manners. And on top of this, craniosacral motion expresses the nature of the fascial net purely, with muscular function completely absent. This permits to conclude that the fascial net of some people favors “flexion disturbance”, that of others “extension disturbance”.

The most general description for the two types is that the midline of the body is anterior convex for the “flexion disturbance” or externals. It is posterior convex for the “extension disturbance” or internals. The consequences can readily be seen. Gravity will bend the midline of externals forward more, that of internals backward. The whole structural dynamics and functional compensation will with externals center around restricting that forward push at the height of the body’s gravity center and finding an optimal arrangement. The picture looks exactly and symmetrically opposite for internals.

The transfer from a functional system to a structural typology can be illustrated more plainly by looking at the legs. The structural norm states that they should show no rotation. This is valid for easy stance and so corresponds to the midpoint of the “neutral zone” of craniosacral motion, its “neutral point”. In flexion, the legs will slightly rotate externally, in extension internally. A leg which is structurally rotated externally will rotate externally a little more in flexion, and it will be rotated externally a little less in extension. The external structural preference of the leg will be an expression of the bias of the fascial net toward external or “flexion disturbance”(5). CST examines the quality of craniosacral motion in the leg regardless of where it is on the identical but much larger structural range. Rolfing will diagnose the structural rotation and normalize it without regard for the quality of craniosacral motion(6). Rolfing analyzes the orientation of the body parts with respect to the three coordinates of space in the “home position” of easy stance. CST deals with the quality of craniosacral motion regardless of from where it starts, where the neutral zone is on the structural range.

Summing up, craniosacral motion appears to serve nicely the purpose of producing a structural typology for several reasons.

1. It originates deep inside the body and spreads out to the periphery encompassing all the body.

2. It seems not dependent on and modified by gravity much, at least in the systemic coherence of the directions all the parts of the body take.

3. Neither does it involve any muscular activity. It so represents the nature of structure or the fascial net purely.

4. It permits to distinguish two manners of “disturbances” which are related as polarities. In each kind, all the parts of the body move directly opposite to the other kind; and in each kind all parts move harmoniously always in the same direction and never the “wrong way”.

Naturally the value of the typology depends on its explanatory power with regard to gravity. It would only raise mild interest without the fact that the structural bias toward external or internal also leads to two entirely different mechanical regimes.

That the typology is indeed of great mechanical relevance is shown by the transmission lines as described by Sultan. They take completely different courses through the body with internals and externals but comparable and similar ones within each group. Transmission lines transmit the weight to the ground. For understanding the concept clearly, two aspects of weight bearing should be kept apart. On a concrete and material level, matter rests on matter, compressing it, all the way down to the ground. The earth by virtue of its rigidity resists and counteracts this pressure, executing an upward thrust to the body by its “normal force”, cancelling out gravity’s accelerating effect. In tensegrity structures the spacers are compressed and bear weight while stability is guaranteed tensionally. In hydrostatic ballons it is the liquid inside which is compressed and bears weight.

On a more abstract level, the vertical line through the gravity center of the body can be considered to transmit the weight down. It is the resultant of all the material parts being compressed.

<img src=’https://novo.pedroprado.com.br/imgs/1989/1032-1.jpg’>
Fig.1 – The graph shows schematically craniosacral motion (exaggerated in amplitude) and the structural point of two bodies. It can be read as the structural and craniosacral rotation of the femur or as the structural tilt and the functional tilting during craniosacral motion of the pelvis. The system on the right shows wide, smooth, and symmetrical craniosacral motion and would be considered normal by CST. Structurally it is far to the external side and therefore not normal for Rolfing. The other system, on the ordinate, is normal from the structural point of view because it shows “no rotation”. The craniosacral motion is staggered, restricted and asymmetrical, and so the body would not be normal for CST.

An iron tube, which is a hollow cylinder, standing on one of its ends should serve to illustrate the situation. The wall of the tube can be imagined to consist of innumerable microscopically thin columns of iron. The metal parts within such a column which are above thrust down on those below, which are compressed and bear weight, and they hand it down to those particles still lower, and eventually to the ground. All these countless columns bear the same amount of weight. The ground exerts a vertical thrust upward to the base of each column which equals exactly the weight bearing down. In the more abstract view, the gravity center of the tube is considered. It is located on the axis of symmetry, far away from the material parts which actually carry weight. The tube is described as a system in which gravity acts on the gravity center, propelling it downwards. Where the vertical axis of symmetry crosses the ground, or better the horizontal plane defined by the lower rim of the tube, earth is described as exerting its upward thrust of the “normal force”. But where gravity and earth are supposed to apply forces to the tube and all along their courses of action there is no matter to be found!

If the iron tube is imagined as bent or buckled, the situation changes. Disregarding shearing forces, the columns now don’t bear the same amount of weight anymore. That column following the line of greatest concavity carries a much larger load. The columns close to it also bear more weight than before although less than that in the concavity. Those on the convex side bear less than before. Consequently, the vertical line through the gravity center which carries all the weight in the abstract view is now very close to the column which materially bears the most weight.

It can be said that the vertical line through the gravity center running through the middle of the material weight-bearing columns it represents in a spatial sense signifies balance of these columns. The structure can be said to distribute weight to the ground. If this vertical approaches or even coincides with the column bearing most of the weight in an unbalanced system, this column or line can be said to bear the weight. It means that one or a few columns now prominently carry a disproportionate amount of weight while others are relieved. The impression of a system distributing weight in a balanced manner is “light”, and that weight is borne comes up as an idea only in unbalanced systems.

In a well integrated body the abstract resultant of the weight-bearing columns goes through the center of the trunk, in front of the spine, where there is little tissue present and none which could bear weight. It expresses balanced weight distribution by the columns all around. Subjectively a mast can be felt there very clearly which holds up the body, with everything around it hanging down and away from it, although the mind knows that there is nothing like a mast there. In an unbalanced body the mast goes through tissue which bears much more weight. This tissue is noticeably compressed, and it reacts to the misuse by thickening and rigidifying in an attempt to fulfill these unphysiological obligations. The columns may be bone or fascia, which impresses then as “fascial columns”.

The appearance of transmission lines in the body so at first signifies imbalance, and secondly these lines identify the columns bearing most of the weight. That the transmission lines are different for internals and externals indicates that their structures are distorted in differing manners, resulting in different mechanics. Typically, with progressing integration the transmission lines become diffuse and are eventually absent. Their disappearance means that weight is now distributed in a balanced manner to the ground.

Transmission lines are so characterized by the abstract resultant of weight distribution coinciding with material fascial columns. They are the shortest, most solid, and least extendable strands of fascia in the body. Conversely, when the body is to be integrated, in the course of which it must lengthen along the midline, these fascial columns tie it down most and present the major obstacle to lengthening, functionally as well as structurally. They need resiliency first and foremost, and lots of it. But lengthening the tissue of the transmission lines is not always and automatically sufficient. Geometry needs to be regarded. The segments must at the same time arrange themselves more vertically and horizontally. Otherwise, the result may well be disintegration because the still unbalanced structure is only deprived of what support it has and threatens to sink and collapse more.

Determining the Structural Type

Pure internal or external types are rarely found. Most bodies have elements of both. Those which are fairly harmonious in one or the other direction are called congruent internals or externals by Sultan. If disharmony is strong he calls them conflicted. For the first group the value of the typology lies in its pointing very specifically to the direction in which the body must change in order to become normal. Put simply, an internal must change in all aspects toward external, an external toward internal, to go toward normal. A body which would be neither internal nor external – which doesn’t exist in an absolute sense – would be normal structurally as far as the typology reaches(7). For the group of conflicted structures it is evident that there must exist internal strain in the fascial network. The harmony of its design, which is preserved in a certain sense by congruent types, is disrupted. Practice has shown as true the theoretical prediction that conflicted types need a certain degree of internal harmonization before the specific intention of Rolfing, creating structural balance in the gravity field, can be pursued(8).

This raises the question of why it is and how it comes about that there is so often conflict. But another question needs to be dealt with first. The concept of conflict and harmonizing the type internally makes it necessary to determine the basic type with which some parts of the body belonging to the opposite type are in conflict. Often this presents no problem because the type is evident intuitively. But sometimes the situation is not clear. And it should also be worthwhile to examine on what intuition is based in the obvious cases.

Sultan names the rotation of the femora as indicative of the basic type in 90% of the cases. He doesn’t explain his choice nor mention in which cases they are not, nor what should then be chosen as the indicator. In practice the criterion serves its purpose well although it is itself in need of some clarification.

A simple way of determining the basic type would be quantitative. If the majority of the parts of the body were external e.g., it would decide that the basic type is also external. The method suffers from the fact that it is not very practical in exactly the close cases which present the problem. It also appears unsatisfactory because it leaves out the aspect of “structural logic” which is one of the major gains of the system.

Since the system is modelled along the lines of craniosacral motion it could be argued that the angle of the spheno-basilar junction should decide the basic type. The two phases are named after its behaviour after all. This meets several difficulties and objections.

1. In practice the angle can’t be assessed visually or measured directly. Perhaps X-rays would be suitable although not practical.

2. Theoretically, it lacks the feature which is so important to Rolfing of an unequivocal distinction in a geometrical sense. Such a dividing line should follow one of the three axes of space. With the angle of the spheno-basilar junction, a dividing line between external and internal could only be found statistically and would always contain a certain degree of arbitrariness.

3. It is unlikely that the angle of the spheno-basilar junction should be decisive for the behaviour in the gravity field and permit to distinguish between two mechanical regimes.

Next in line as a candidate would be the occiput. If it is wide, the type would be external, if narrow, internal. It would also meet the second and third objections to using the spheno-basilar junction.

Following this, the degree of the spinal curves could be taken as indicating the structural type. In flexion it straightens as a whole. The occiput takes the skull along into a forward down rotation and posterior shift, the sacrum induces a pelvic tilt in the posterior direction. In extension, the spinal curves are augmented. A difficulty is posed again by the fact that determining a certain degree of curvature, defined radii of the curves, as normal is always arbitrary in some way. It is also difficult to see why a little more or less curve in the spine should make a significant difference in the body’s behaviour in the gravity field. The situation is different of course when the direction of the curves is reversed. This would certainly be indicative of an external structure and constitute a clear mechanical difference. But this group comprises only part of the external structures. Other structures which don’t show reversed directions of the curves but only a too straight spine are also external.

At the spine, the mechanical aspect becomes more prominent, too. Especially in its lower part gravity is a factor. But also other mechanical influences like chronic muscle contraction or fascial shortening as a consequence or compensation modify the spinal curves. This also raises the possibility and frequency of conflict. The skull is perhaps relatively uniform in its structural tendency(9). If it is taken as the reference point, the farther away from it the situation is examined, the more often conflicting structural states should be found.

It should be emphasized however that the axial skeleton, skull plus spine, forms a unit as far as craniosacral motion is concerned. It is not that the skull moves and so causes the spine to move accordingly. Since pressure in the liquor system seems to be the causal agent, which travels extremely fast in a closed hydrostatic system, the motion of the bones of the skull and the spine is practically simultaneous. If there are differences in the onset of the movement, they would be due to differences in the resilience of the dura. The skull and the spine form something like the primary unit of craniosacral motion, which is synchronous in it.

This changes when the rest of the body is considered. At the lower pole of the spine, the sacrum rotates forth and back around a transverse axis which Upledger places at about one inch in front of S2. In flexion the base of the sacrum moves back, the apex forward: the sacrum aligns itself more vertically. In extension it moves closer to horizontal. If the bony pelvis were one rigid ring, the pelvis as a whole would follow the movement of the sacrum exactly. It does so only to a limited extent, with a certain delay. For a pelvis perfectly horizontal at the neutral point of craniosacral motion the situation would look like this: in flexion it goes into a posterior tilt, in extension into an anterior tilt. An external pelvis would be in a posterior tilt at neutral, go a little more into it with flexion and in the opposite direction, toward horizontal, in extension. The tilt of an internal pelvis would be anterior all the time, and it would increase with extension and diminish with flexion.

This provides the first sharp criterion for separating internal and external because the structural norm for the pelvis is defined exactly as “no tilt”, the pelvis being exactly horizontal. This dividing line is not only absolute in geometrical terms but is also of primary mechanical relevance. The weight of the trunk falls behind the rotational axis through the hip joints when the tilt is posterior, and no matter how minimal the tilt may be, the weight will always push down the back of the pelvis more if the segmental gravity centers are aligned on a vertical. With an anterior tilt, the pelvis will always be pushed down more in front. As a consequence, the two different kinds of tilts necessitate two entirely different sets of adaptations through the entire body in order to compensate for the primary tendency set at the pelvis. The two mechanical regimes, in their structural and functional consequences, will be radically different in every respect(10). The crucial importance of the “horizontal pelvis” suggests that the direction of its tilt should be the primary factor in determining the basic type(11).

However, the pelvis changes shape internally with craniosacral motion, too. This indicates that there is movement in the sacroiliac joints(12). Joint analysis produces highly differing results and opinions. In contrast to this, craniosacral motion seems to be fairly uniform and the same in most bodies. Essentially, the pelvis widens in front with flexion and narrows in extension. The ischial tuberosities come closer together in flexion and widen in extension. From this, a simple model of the sacroiliac joint can be postulated which explains physiological movement fairly well. The joint surfaces are imagined to be planar, with sacrum and ilia rotating around each other about an axis perpendicular to the articular plane. The axis would point from the sacral joint surface lateral and slightly posterior and down. The sacrum itself rotates around a transverse axis, and because the axes of the two sacroiliac joints are not in line with it, the ilia perform a “screwing motion” when the sacrum rotates. It is easier to visualize the movement with the sacrum fixed and the ilia rotating. Then in flexion the ilia rotate anteriorly with respect to the sacrum, the anterior superior iliac spines going wide and the tuberosities narrowing(13). The sequence looks about like this: first only the sacrum rotates back in flexion. The ligaments which transfer the motion to the ilia are being tensed and this allows for a little time to elapse until their slack has been taken up. Very soon the ilia begin their “screwing motion” – they rotate “externally” – which depends more on the nature of the deep fascial tissue, its design, than on the sacral joint surface acting directly on the bone of the ilia. After this, they are taken into the posterior tilt by the sacral motion. In some ways, as indicated by the landmarks of the bony pelvis, the motion of the ilia relative to the sacrum is in the opposite direction of when they tilt posteriorly with the pelvis as a whole. So the tuberosities which go medial in flexion would have a tendency to go back from the ilial motion alone, but they actually go forward with the posterior tilting. The posterior tilt overrides the internal motion because of its larger range.

The important aspect is the slight lag in the transfer of the motion from sacrum to ilia which is a condition for internal shift of the bony pelvis. This repeats itself at the hip joint. The axis of the neck and head of the femur is perpendicular to the plane formed by the ring of the acetabulum. This axis, from the center of the acetabulum outwards, points lateral, down, and slightly forward. It turns back more in flexion, going with the external motion of the ilium, and when the slack of the deep fascial tissue has been taken up, moves the femur into external rotation. The situation is identical at the knee and the ankle joint.

The craniosacral motion in this view originates in the “semiclosed” space contained by the dura, which is affected first. By way of its attachments to the bones of the skull and the spine it affects the axial skeleton. From there the movement spreads to the appendicular skeleton successively by way of the deep fascial tissue. The medium of propagating the motion is fascia(14), but this motion travels “deep”, along the bones, to the periphery. The moving bones and deep fascia take along the soft tissue surrounding them.

Translated into the structural field, an external or internal type means that the neutral point around which the bones move is shifted for all of them toward one and the same pole. Furthermore, the deepest fasciae as a continuous system fit the bone pattern and assume one of two distinctly different shapes. And thirdly, the fasciae of the soft tissue more toward the periphery of the body would also divide into clearly separated internal and external shapes.

The logic of craniosacral motion would determine the basic structural type according to that of the axial skeleton, especially the skull. The farther away craniosacral motion travels, and the farther away the body is examined for the structural deviation corresponding to the directions indicated by craniosacral motion, the more probable conflict would become. A body with conflict in skull and spine would be severely conflicted, a body with disparate ilia or ribs less, and a body with conflict perhaps only in the soft tissue of the distal extremities would be called mildly conflicted at most.

But the logic of craniosacral motion runs into conflict with the structural logic which calls for a gravitationally relevant part to serve as the indicator for the whole system. This should be low. The femur looks like a good compromise. It is not too far from the spine and low enough to be relevant for weight considerations. In addition, it has the welcome feature of being aligned along the coordinates of space in normal structure. The knee points straight forward. The line through the epicondyles is exactly transverse, i.e. horizontal in the frontal plane. If this line is turned out, the femur and the basic type is external. If it points medial, it is internal and indicates the internal type.

Some objections can be raised against the femur, too. For one, the transverse line through the epicondyles is not marked exactly by nature. This is true for all bones of course, and it can be said that the situation is favorable at the epicondyles because with slight flexion and extension in the knee this line can be determined with confidence. A lack of certainty seems to arise more often from the patella influencing the appearance. The patella which is so obviously in evidence is somewhat variable and cannot be taken as an absolutely reliable indicator of femoral orientation. Similarly, when the soft tissue is used to aid in deciding on the rotation, it must be kept in mind that it may go with the rotation of the femur or against it. It is necessary to remember that the rotation of the femur is at question, not that of the thigh, as long as the argument is still in the field of anatomy or CST and not Structural Integration.

Another problem comes up when one realizes that the rotation of the femur also depends on the ilium. It can be imagined that the ilium is strongly external, the femur less so. Then the femur appears as external with respect to the coordinates of the body, but relative to the ilium it would be internal.

These questions are generally not very important and pose no serious problems. Not often, but now and then they need to be considered. On the other hand, recognizing them when they exist and understanding their nature would aid the progress of structural knowledge remarkably. Another phenomenon needs explanation however. It consists of the fact that with many internals the knees actually look out – they point lateral -, which naturally gives the impression that the femora are rotated externally. Closer analysis shows that “internal rotation” as the structural equivalent to the craniosacral functional term does not only imply a one-dimensional rotation in the anatomical sense, around a vertical axis through the hip joint. Internal rotation generally goes along with abduction and flexion in the hip, external rotation with abduction and extension. Cautiously formulated, it seems that internal rotation in the anatomical sense predisposes the femur strongly to also abduct, external rotation to adduct. The correlation seems more pronounced with externals because vary rarely one sees externals with the knees relatively wide apart. Internals with adducted femora – knees close together – seem to be less rare. It is perhaps premature to identify internal rotation and adduction of femora as a specific conflict although the impression is suggestive.

The problem with abduction is that it doesn’t exist in a pure sense. When the leg is abducted functionally it also rotates externally to some degree. Furthermore, this rotational “contamination” of abduction is more marked with increasing flexion of hip and knee, it is least with hyperextension of hip and knee. The first is easily verified when abducting in sitting, the second in standing in the appropriate functional arrangement. Internals tend toward flexion in hip and knee while externals lean more towards extension and hyperextension. So it makes sense to have internals stand with the feet together and straight, extending knees and hips. Abduction and flexion are so minimized and reveal the internal rotation of the femora. This situation illustrates a feature of the fascial system: it can widen less in back than in front. When in abduction the femur goes lateral, away from center, the tissue in back restricts the movement first, effecting external rotation.

So while the femora are generally useful in diagnosing the basic internal or external organization of the body, they lack decisiveness in pointing out two different kinds of mechanical regimes. It cannot be seen immediately why the femora rotated a little internally or externally should make a radical difference(15). This is very different when the tilt of the pelvis is taken as the decisive factor. Ida Rolf always emphasized the horizontal pelvis as a key to normal structure. In a similar way, the anterior or posterior pelvic tilt appears as the key for deciding on the internal or external organization of the body. With the anterior tilt, the weight vector from the upper body passes down in front of the hip joint, with the posterior tilt in back. The hip joint is “The Joint that Determines Symmetry” (Rolf, p. 143), and as far as front-to-back balance is concerned, the side on which the weight passes the hip joint makes a mechanical difference around which the whole body has to adapt.

With the shift of focus from the femora to the pelvis not only the area under consideration has changed but also the level of abstraction. Pelvis means the pelvic segment here and not only the bony pelvic ring. Bones are of secondary importance in Rolfing, but because they are such prominent and immutable “hard facts” they easily seduce one to stick with them and forget that they are where they are because the soft tissue is the way it is. “Pelvis” as the pelvic segment places the concept firmly in the field of Structural Integration.

A completely different kind of movement should illuminate the situation: Folding (Notes on S.I. 87/1). Fig.2 shows the sequence of “Unfolding”, in the course of which two postures appear which are not internal and external structure but imitate them posturally. Structure should be thought to be normal. The system has two main folds: the pelvis with the hip joint in back and the knees in front. In addition, two “semi-folds” can be discerned. One is the heel which goes back in Folding. The other is the cervico-thoracic junction which goes forward. The latter almost looks like a true fold because neck and head go in the direction opposite to that of the trunk. It should not be considered as such however, mainly because head and neck should not take an active part in balancing the body in gravity. The head should “float” on top, and its behaviour in movement should serve the main purpose of keeping it horizontal.

<img src=’https://novo.pedroprado.com.br/imgs/1989/1032-2.jpg’>
Fig.2 – “Unfolding”. The arrows give the direction in which gravity pushes out the folds and semifolds. In the second from left all the folds are very close to the Line, representing internal stance. The next shows the structural norm, where all the folds are exactly on the vertical Line. In the last all the folds have crossed the Line and are now pushed out exactly in the other direction by gravity. It represents external stance.

When continuously “Unfolding”, all the folds approach the Line. Close to it they represent internal posture which many internal structures assume. Gravity acts to push the folds out again to the side from which they were coming. With all the folds exactly on the Line, posture resembles that of normal structure. No horizontal push from gravity exists. When the movement is continued further, all the folds cross the Line to the opposite side. Gravity now pushes all of them out to the side opposite to that from which they started. The posture resembles that which external structures often show. The zig-zag line the folds describe is exactly reversed, indicating that gravity acts on every part of the body in an exactly reversed manner as far as horizontal push is concerned. Gravity tends to fold down the body in two distinctly different ways which are symmetrical.

For a well integrated body it is easy to sense some major characteristics of internal and external structure by going forth and back between the two postures. On the external side, the pelvic shift is anterior and the tilt posterior, the pelvis sinks down in back. There is horizontal tension in front of the body which pulls the anterior superior iliac spines lateral. In back the pelvis loses tone and the ischial tuberosities collapse medially. The legs want to rotate externally. On the internal side, the pelvic shift is posterior, the tilt anterior. Tension in front is gone and the anterior superior iliac spines are left to come closer together again. The pelvic floor acquires tone, and the ischial tuberosities go wide. The legs want to rotate internally.

The exercise suggests that the sagittal shift of the pelvis might even be more important than the tilt. This would correspond to the earlier suggestion that the midline is anterior convex with externals, posterior convex with internals. Among internals, where the anterior tilt and the posterior shift are usually congruent in free stance, a large number of sleeve-supported structures or downright internal locked-knee types exist. The pelvic shift is anterior with them, but the tilt is still anterior although less so than in free stance. The pelvis also looks fairly wide in front, but the ischial tuberosities are not close as one would expect. The legs are still internal, and the upper body is usually very strongly so, with deep spinal curves and a very flat chest. Likewise, some externals can be found where the pelvis is shifted posteriorly. The posterior tilt is very marked, but the legs are not so strongly external. So it seems that the pelvic tilt is the most constant feature, especially when the body is examined in a position close to normal in free stance.

The Possible Genesis of Internal anal External Structure

The question is here not only how internal and external structures come about but also where conflict enters. The most naive guess would assume that we are either born as congruent internals or externals with the stress of life inflicting conflict on the “perfect baby”. However, structure and other features we are born with are more a design than primarily manifest reality. The naive view would imply that we could see two distinctly different structural types of babies! This is not true of course, and so the notion that the type is genetically determined like male and female e.g. can be dispelled. This does not mean that there may not exist some sort of hereditary disposition, but the point of view cannot be examined before the nature of internal and external structure is known better.

When looking for internal and external traits in babies, two kinds of difficulties arise. First, babies are not erect in gravity, standing on solid ground, and secondly their bodies are extremely flexible and variable in appearance. Intersegmental characteristics can hardly be determined. Intrasegmental signs are more stable however and promise to offer some clues.

At birth, the cervical and lumbar lordoses as “dents” in the C-curve are already present although very little marked. They acquire their normal degree or excessive depth later through function. It is dubious to type a newborn’s spine because a normal degree of curve cannot be stated with objective and absolute exactness. It could perhaps be held to tend toward external although certainly not of the qualitatively imbalanced type (Notes on S.I. 86/1, p.6). The front of the chest generally appears flatter than normal, the angle of the ribs is relatively steep. So the ribcage appears more internal than external, and this may lead to postulate a primary conflict in the thoracic segment between external spine and internal ribcage.

The bony pelvis is very narrow and therefore internal. However, the sacrum sits in it more in the external manner. Certainly one doesn’t find the deep anterior dissociation of the base of the sacrum from the upper posterior aspect of the ilia. The sacrum goes with the spine originally, and so perhaps another basic conflict can be suspected for the intrasegmental configuration of the pelvis. Concerning the tilt, the pelvis seems to be in line with the rest of the trunk and so tending toward external, maybe mediated by the spine and sacrum, while with respect to the thighs it is very much tilted anteriorly. This is evident when the legs of a baby lying on its back are pulled down flat on the table.

The legs are clearly bow-legs and therefore internal. There is also something like a primary conflict at the ankle joint, however. The joint axis is not transverse but lower medially. So the heel is by necessity, but also by design, valgus. This creates a break in the (hypothetical) weight line: it comes down from lateral at the knee to medial at the ankle and then turns out lateral through the heel again. In a simplified and speculative way it could be said that with internals the foot adapts to the leg, with externals the leg adapts to the foot(16).

However, the forefoot seems to be abducted. An intrasegmental primary conflict can be suspected between an external tarsus and an internal antetarsus, too.

The overall impression is that babies tend structurally toward internal with some external facets or potential. The main implication of this statement is however that babies are fairly uniform in their structural appearance. It can of course not be excluded with certainty that better structural understanding might eventually provide clues which allow to predict an evolution toward internal or external.

The situation becomes much clearer when the domain of Structural Integration is entered, which is at the time when infants begin to stand up on their feet. Besides more anatomically fixed adaptations to the erect stance like e.g. the design of the feet or the foramen magnum, the main feature in the structural view is the strong flexion in the hip joints. It has a functional and a structural aspect. The first states that the tonus of the flexor muscles is higher than that of the extensors. The second emphasizes that the fascial tissue on the flexor side – through the groin – is shorter than that on the extensor side. It is reasonable to think that this is a phylogenetic remainder as the original design of man is still somewhat for a quadruped. The angle at the hip is there roughly 90°, which for erect stance has to open up to 180°. But also purely structurally the fact makes sense because the fetus spent all its intrauterine life with extremely flexed hips. So the tissue in front of the hip joint simply never had the opportunity of being stretched and lengthened.

<img src=’https://novo.pedroprado.com.br/imgs/1989/1032-3.jpg’>
Fig.3 / 5-month and 16-month old boy illustrating some early structural and functional features.

The flexed hip is central to this hypothesis. It forces the pelvis into a marked anterior tilt in standing. If the spine stayed straight, the upper body would lean forward strongly and standing would be impossible. The thorax needs to be brought back over the pelvis and the hip joint. This induces a deep lumbar lordosis in a spine which is still highly flexible. Gravity then acts on this arrangement in the sense of magnifying anterior pelvic tilt and lumbar lordosis. In the thorax which is tilted back it tends to push its front, the chest, back onto the spine. Its weight would drag forward the upper back and so induce and augment the thoracic kyphosis. This in turn would make it necessary to bring back the head over the thorax and the pelvis, in this way increasing the cervical lordosis.

This arrangement is congruently internal, it originates in the shortness of the groin, and it is necessary because the major segments must be aligned somewhat along a vertical in order to guarantee a balance(17) without which the child is not able to stand erect.

The description so far has only taken into account some fascial properties of structure and gravity’s impact on it but has begged the question of what it is that does approach the segments toward the vertical line. This is of course musculature, and if one observes infants trying to stand up and taking their first steps it is evident that they give it all they have.

Looking at this functional side very much in evidence and essential for balance, some mechanisms can be discerned. One favorite seems to be the drawing back and together of the shoulders. This helps holding the thorax back. It also lifts the chest in front and drives the LDH forward! If the fascial net adapts to this posture, the shoulder girdle, the upper back, and perhaps the chest would tend to turn external structurally. The erector trunci is certainly also used to aid in tilting the thorax back. It does not extend the spine however but mainly shortens it, driving at least the lumbars forward more.

In the overall side-view the starting position is similar to that of the internal posture shown in Fig.2. The two main folds, knees and pelvis, are pushed out forward or back by gravity. They can only be contained by muscular force. The farther out they are the more muscle activity is needed. It is advantageous and even essential to keep them as close to the Line as possible. For the knee mostly the quadriceps would work, for the ankle the soleus. The pelvis would be refrained from being pushed out back by the gluteals.

The goal would be reached when the gravity centers of the segments are very close to the Line and can be easily held there. If they were in line exactly – and with no rotation – no effort would be needed to hold up the body. The second condition which needs to be met toward this end is a very high degree of resiliency in the connective tissue. This would permit the segments to be aligned vertically without resistance. With the connective tissue not so perfect, fascia will tend to draw the folds out, which tendency would be reinforced by gravity. So for the internal one can expect a kind of optimum where the folds are present: not too much out for having to work hard against gravity and not too close in for having to pull the segments in line against the resistance of fascia. The connective tissue is stretched and lengthens in the course of growing, perhaps by an innate factor, certainly by movement especially when it is appropriate, of the extension type. Some bodies seem to fare well in this, others with rigid connective tissue don’t succeed well and have a hard time all their life containing the folds.

There is a much more radical solution however. When the folds go close and closer to the Line and then cross it, assuming external stance (Fig.2), all the muscles mentioned are suddenly not needed anymore. Gravity now pushes the folds in the other direction. Typically, strong internals have hypertrophic gluteals while with some externals who seem to stand and move permanently in the external regime they appear near-atrophied. The anteriorly shifted external pelvis is now refrained from going forward more by the flexor muscles, including the abdominal wall, which because stronger than the extensors have an easier job. Furthermore and especially when tired, the external posture allows to slip into sleeve supported stance which is advantageous economically. A structure adapted fully to it results in the external locked-knee type.

So if the original goal is formulated as achieving vertical alignment from a primarily internal posture – and structure conforming with it more or less -, internals can be called underachievers, externals overachievers. The decisive factor which makes the types so extremely relevant lies in two entirely different mechanical regimes to which they belong.

Mechanical Considerations

Internals and externals are in many ways symmetrically opposed as e.g. concerning rotation of the extremities. But if their mechanics are under consideration and not only geometry, it often turns out that symmetry is broken. One major asymmetry which concerns the pelvis and the legs seems to be formed by the impression that with internals the lower girdle is a tensional or tension dominated system, with externals a compressional or compression-dominated one.

Internals have an anterior pelvic tilt. Seen from the side, the supporting beam of the femur holds up the pelvis eccentrically, in back of the pelvic gravity center. The weight of the upper body passes down in front of the hip joint and can be visualized as hitting the pubes. These are pushed down and turned back some. The thighs go wide to make room for the pubic area descending, or looked at it the other way: the pubes push the thighs lateral. This may in part explain the internals’ tendency for abduction of the thighs. It would mean that abduction is not a feature of the extension phase of craniosacral motion but one of gravity acting on structure.

The pubes with the weight on them are not supported by any firm structure below. The anterior tilt must be contained tensionally. This is done effectively by the hip extensors. The tissue along the gluteus maximus possesses excellent leverage to do the job. But also the hamstrings are well suited to help them because the tuberosities are high and way out in back. The extensor fascia is the structural base for compensating for the anterior tilt. Its downward pull on the posterior pelvis balances gravity’s impact on the pubes. It is often tight or taut. It is overstretched – constantly longer than it would be with the pelvis horizontal – and it reacts to the functional misuse by hardening and thickening. But alone it would not succeed in limiting the anterior tilt. It would be stretched maximally, and in the long run it would every now and then give a little more. The anterior tilt would increase progressively over the years.

With some structures this is exactly the case. But the fascia has allies in the form of the muscles accompanying them. Their tonus adds to the passive tissue tension and so helps containing the anterior tilt. In a certain sense the adjunct muscles protect the fascia from being overstretched too much. As a result, the hamstrings and the gluteus maximus are hypertrophic with many internals. The regulation of the anterior pelvic tilt by the extensors is quantitative, on a sliding scale. When they are maximally relaxed, the pubes are maximally low, the tilt is extremely marked. With some tonus in the musculature the tilt is less and in “working condition” in which most internals seem to move and get through their day. With still more effort, the pelvis can approach horizontal or even go into a posterior tilt and external posture momentarily.

There also seems to exist a progression with age. Most younger internals keep their tilt in “working condition”; they regulate it easily with their extensor muscles. When they grow older, the muscular effort makes itself felt more strongly, and more and more internals “drop out”. They give up on compensating and let their pubes rest down between the thighs. This whole area is then massive, toneless, and glued together. A typical example is given by many old football players.

The extensor compensation of the anterior tilt has functional advantages. But it is also highly unfortunate in another respect. The downward tension of the extensors combines with the weight on the pubes to compress the hip joint considerably. The os coxae is pulled tightly down on the head of the femur. This results in the joint capsule and the tissue around it becoming hard and in high intraarticular pressure which resists movement and must be overcome by additional muscular effort. This in turn contracts and compresses the body further. In the long run this might be a factor in the genesis of degenerative disease, osteoarthrosis of the hip joint.

There exists another mechanism which compensates for the anterior tilt and which can nearly always be found, usually to a considerable degree. It consists of the abdominal wall, mainly the rectus abdominis, pulling the pubic bone and the front of the ilia up. It probably forms the rationale behind the wide-spread idea that one has to strengthen the belly muscles. Structurally it is much more disruptive than the extensor compensation and often outright devastating. Because of its extreme leverage it pulls the chest down and flat very effectively and so bends the thoracic spine powerfully. To keep the chest fixed in space and make this mechanism effective calls for vast contractions and fortifications in the whole upper body.

The fasciae of the hip extensors and the abdominal wall are so usually in secondary shortness: overstretched and rigid. Making them more resilient presents the danger that the structure drops more into its aberration of the anterior tilt, or it forces the body to use the muscles more. Both effects would be a sign of structural disintegration. The fasciae in primary shortness, hard and rigid because always shorter than with the pelvis horizontal and functionally underused, must be released concomitantly. They are mainly but in varying proportion those of the iliacus, the abductors, and the rectus/tensor/sartorius group.

The weight of the upper body on the pubes makes it advantageous to take the thorax back some. Usually it is tilted posteriorly therefore, which brings the weight more back toward the hip joint although it can never be placed directly on top of it in free stance. Besides severe consequences for the upper body, this adaptation also changes the picture at the pubes. The weight does not come straight down from above but slightly from behind, too. This renders the situation concerning the sagittal pelvic shift labile. Many internals “choose” the solution of letting the pelvis and the pubes slip forward – the tilt still being anterior – and coming to rest in sleeve-supported stance. If the structure adapts, this often results in the internal locked-knee type. In free stance, the sagittal shift of the pelvis is posterior and the pubes are down and back.

The weight on the pubes not only tilts the pelvis down in front but also produces posterior shift. Gravity pushes the pelvis and with it the hip joint out in back. This is the posterior fold in Folding, and it cannot be contained only passively. Muscles are always involved. The fascial sling in back which must be supported by muscles is larger than that active in limiting the anterior tilt. It reaches at least from the thighs up to the lower back.

The knees constitute the anterior fold in Folding. Except for the locked-knee type, which is not normal and not at issue here, the knees are slightly bent with internals. Some of them are not even able to extend the knees completely and certainly not to hyperextend with maximal effort. Fascia prevents it. Similar to the posterior pelvis, the flexed knees cannot be contained passively alone but need supportive muscle tension from the vasti – not the rectus femoris! This also often results in muscular hypertrophy besides thick and tense tendons and ligaments.

At the ankles, the weight from above also comes down slightly from in front. And again the flexion in the ankles cannot be restrained solely by fasciae but needs active muscle tension. This is provided by the soleus.

The lower girdle of internals is so characterized by flexion of hip, knees, and ankles. At every joint, fascia needs muscular support to contain gravity’s impact which is free to push the joints into further flexion. The full picture of a highly or better over-competent internal lower girdle is furnished by some bicycle racers who display hypertrophic vasti and calf muscles and narrow knees and ankles, secured by tight fascia.

Externals have a posterior pelvic tilt. The weight vector of the upper body passes down behind the hip joint. A minority of externals which are called “symmetrical externals” here is examined first. “Symmetrical” means that their lower girdle is also a tension-dominated system like that of internals with only a symmetrically reversed tilt. The legs except for their external rotation are also similar: the knees are flexed or nearly extended but not usually hyperextended. The pelvic shift is also posterior. This means that there is not much sleeve tension in front, and intrasegmentally the pelvis is therefore not as broad and flat as with many other externals.

The weight of the upper body can be visualized as sitting on the sacrum and pushing down the back of the pelvis. There is also nothing solid beneath it to support it, and so compensation must also be tensional. In this case the downward pull on the pelvis is in front. The responsibility lies mainly with the abductors and the rectus/tensor/sartorius group. But leverage of these fasciae and their accompanying muscles is much less favorable than that of the extensors in their internal counterpart. They have a much harder job. Consequently, symmetrical externals seem to give up more often and sooner than internals, and the back of the pelvis drops far down behind. This presents large problems for integrating them. The pelvis must literally be heaved way up to get over and on top of the femora. Often only then further difficulties manifest, especially an extreme lack of length in the abdominals and adductor problems which were masked before.

But going with the posterior tilt and letting the back of the pelvis sink also offers some advantage for the compensating fascia in front. It results in the pubes going up high and somewhat forward. This improves leverage for the adductors, especially when the legs are rotated externally to a marked degree. The adductors then impress as strong columns which are completely displaced however: in front of the body instead of medial. The two aspects of being a tensional system but going relatively far with collapse explains the frequent although not always present picture of symmetrical externals: the musculature of the lower girdle is well developed but soft.

The upper body just as with internals tends to keep the weight more toward the hip joint, which is forward in this case. The thorax goes forward. But unlike internals which tilt the thorax back and which is possible there because the spine reinforcing the back holds up, symmetrical externals cannot tilt the thorax forward. The front of the trunk doesn’t hold it up from below. So the upper thorax only hangs forward, bending the midline forward. Together with the posterior pelvic tilt, this results in the back and the spine up to T1 approaching the form of a C-curve over its whole length. Sometimes a lumbar lordosis is interspersed which can actually be very marked. It always has a small radius however, and so these structures still show the feature of a very long and marked thoracic kyphosis. The lumbar countercurve, when present, doesn’t change the basic situation which is characterized by an upper thorax leaning and slumping forward on top of and “resting” on the back of the pelvis hanging down low. It may ease the load some, but it must also be suspected that this is at the cost of conflict, either between sacrum and lumbars or ilia and sacrum.

One more peculiarity of symmetrical externals deserves to be mentioned. Their posterior pelvic shift is not clearly defined and fixed as that of internals or the anterior shift of the usual externals. They can also go into a sort of sleeve-supported stance by shifting their pelvis forward. But unlike the other externals, the gain is smaller. The pelvis is so far down behind the heads of the remora that they don’t succeed in getting it over on top of them but simply push the femora forward ahead of the pelvis. The difference in the mechanics shows in the chest which tends to collapse more with functional anterior shift while with “true” externals it is supported better.

Regular externals show a clear anterior pelvic shift. But it is not only the pelvic area which is in front of the Line. The bony pelvis appears as shifted forward on the femora. The statement may sound strange for anatomical reasons: the acetabula have to fit the femoral heads and cannot slide forward on them. It can be explained structurally however, at least partly. The intrasegmental external configuration places the segmental gravity center a little more in front in the pelvis, and at the same time the acetabula turn back some. The posterior tilt is often not very marked because the weight of the upper body is very nearly centered on the femoral heads, only very slightly behind. It shows clearly when the anterior shift is cancelled functionally by bringing the pelvis back in line. The weight comes from above and behind, but because it is not much eccentric it only weakly pushes the pelvis with the hip joint forward more. The hips are therefore extended or hyperextended, and the knees do the same and are never clearly flexed.

The main feature and decisive shift in quality is that the bony pelvis sits almost exactly on top of the femora which because of the extension of the knees are centered on the tibiae. The weight now travels straight down through the bones and so the system acquires compressional properties.

<img src=’https://novo.pedroprado.com.br/imgs/1989/1032-4.jpg’>
Fig.4 – Three different kinds of relationships between bony pelvis and femur and the vertical; regular internal on the left, symmetrical external at center, regular external on the right. The first two must be balanced mainly tensionally, the last has compressional properties. The schematic drawing of a “seesaw” added shows the mechanics more clearly. Externals shift the horizontal beam forward so the weight of the upper body hits the femur almost exactly and axially.

The main advantage of the external compressional system is static. The bones carry weight passively, and only minor tensional corrections are necessary. This relieves the musculature a great deal from having to balance the structure functionally. The disadvantage lies with the dynamics, for which tensional systems are better suited. There is a kind of reciprocal relationship between stability and mobility.

Another difference is also of interest. In tensional systems, the exact form of the rigid members is not so important as long as they fulfill their function as spacers. A tent can be erected and balanced also if the tent poles are not exactly straight. In compressional structures the form of the bones becomes more important because compression induces internal shearing in addition to tension. The femur appears as well adapted to this function because of the anterior convexity of its shaft. It so redirects internally, without involving fascia, the slightly forward push of the weight above back to vertical where it passes it on to the tibia. The different mechanics of internal, symmetrical external, and external structure can be sensed easily and clearly when experimenting with one’s own body, imitating them posturally. With the tensional internal arrangement, the folds are pushed out in the direction of Folding and must be contained muscularly. The dynamics is between “too straight”, the folds very close to the Line, and “too loose”, the folds far away from it. The first case requires effort because the resistance from tight fascia must be overcome, although gravity’s effect becomes nearly negligible. In the second, the fascial net is relaxed and offers no resistance, but gravity’s effect is now marked and demands a noticeable muscle tonus. Somewhere in between is the structural point of least effort.

<img src=’https://novo.pedroprado.com.br/imgs/1989/1032-5.jpg’>

The symmetrical external posture is even more demanding. Part of it is explained by the less favorable leverage with which muscles must do. But the situation is in another way asymmetrical, too. Unlike the internal posture, the symmetrical external one shows no definite posterior pelvic shift. Gravity does not push the pelvis with the hip joint back out because the pelvis is not really a fold here. This is higher up, and so the whole section of the body between about the waist and the knees seems to be tilted back- posterior at the waist, anterior at the knees. This sometimes looks as a solid block with its weight pushing the distal remora massively forward on the tibiae and calling for resolute compensation by the knee extensors. With both tensional systems one feels a springy quality. They always require active muscle tension, but the folds are easily modulated by more or less of it.

When going into external stance, bringing the pelvis forward and on top of the femora, this suddenly changes. One suddenly feels bones standing on bones, the lower girdle being supported from the ground up(18). Muscles are relieved from having to work constantly. They only bring back the system when it is disturbed or changed voluntarily. A further remarkable difference to the tensional systems is that such change is not on a uniform scale but can be in one of two completely diverse directions. The system can go toward symmetrical external, acquiring tensional properties, or in the direction of the external locked-knee type and sleeve-supported stance. In the latter the main folds of pelvis and knees are definitively on the other side of the Line, opposite to that of internals, symmetrical externals, and Folding.

It is interesting that the sagittal pelvic shift reappears as a mechanically relevant factor, especially in the tension/compression context. The internal locked-knee type with its anterior pelvic shift often seems to acquire some compressional quality, too. So an anterior shift seems to be related to a more compressional character of the lower girdle or at least makes it possible. The posterior shift is associated with a tension-dominated regime.

<img src=’https://novo.pedroprado.com.br/imgs/1989/1032-6.jpg’>
Fig.5 – Examples of the four types described: regular internals (1), internal locked-knee types (2)

<img src=’https://novo.pedroprado.com.br/imgs/1989/1032-7.jpg’>
symmetrical externals (3), and regular externals (4)

Structural Dynamics of the Lower Girdle

The hypothesis concerning the genesis of internal and external structure stated that small children begin tendentially as internals. Gravity acts on it and forces musculature to compensate its effect. Some organisms attempt to minimize this effect and the effort needed to check it by getting the segments close to the Line. This results in internal structure. Others choose the more radical solution of adopting external posture, becoming structurally external, which means that they function according to completely different mechanical principles.

In both cases of aberration, internal or external, gravity still acts to bring the body down although in different ways for both. Bodies seem to react to this with greatly varying intensity. Some appear to go a long way with gravity without resisting much. Such bodies impress as heavy, slow, and sometimes literally crushed. Others don’t accept anything and react and overreact promptly whenever any part threatens to collapse. This suggests that a concept may be introduced which could be called “collapse tolerance”. The heavy and crushed bodies have high collapse tolerance, the rigidly erect little of it. Ida Rolf’s only vaguely defined “hyper-erect” type would be an example for the second (Rolf, p. 72).

<img src=’https://novo.pedroprado.com.br/imgs/1989/1032-8.jpg’>
Fig.6 – The main characteristic sign for the internal foot seems to be a lateral convex midline with a varus heel and an adducted forefoot, for the external foot a medial convex midline with a valgus heel and an abducted antetarsus. In a collapsed internal foot the lateral convexity is weak, the tensional system is still visible (1). In the over-compensated internal foot the lateral convexity is marked (2).

<img src=’https://novo.pedroprado.com.br/imgs/1989/1032-9.jpg’>
In the constricted (over-compensated) external foot the medial convexity is expressed weakly (3), it is marked in the collapsed external foot (4).

Many bodies suggest that compensation of collapse is not merely a matter of degree but that there actually exist two different groups. One comprises bodies which have collapse tolerance and go with collapse more or less before the organism intervenes. The other consists of bodies which don’t have any tolerance but actually overcompensate readily. The foot serves well as an example. The weight of the body pushes down the longitudinal arches constantly. Some bodies go with it; their feet have low arches or are flat. Others not only don’t allow collapse but raise their arches actively, resulting in fixed high arches. In practice it is almost always simple to assign the longitudinal arches of the feet to the “too low” or “too high” group. Normal arches in the Rolf sense, which have just the right height and the exactly right degree of resiliency, don’t exist in reality.

Both collapse and compensation, which properly means over-compensation, look different with internals and externals. Internals as tensional systems come from “too internal” more toward normal according to the hypothesis presented. This suggests that the quality of their connective tissue and its collagen, which is largely determined genetically, assumes an important role. If it is relatively soft, offering not very much resistance to being stretched, the body is easily held near normal. When the fasciae are tight and hard, muscles must always work hard either containing gravity’s effect of pushing the folds out which is marked in strongly internal posture or overcoming strong tissue resistance when keeping posture closer to normal.

So with internals the degree of how well they succeed in approaching normal seems to separate two groups or tendencies first on which then the collapse/compensation dynamics acts. “Soft internals” would be those which approach normal easily without having to develop their musculature. They often tend to go into sleeve supported stance and become internal locked-knee types. The collapsed version shows a soft, rather slim figure with a strongly curved back indicating collapse of the upper body. The lower girdle has partly a compressional character. This type is often exemplified by mannequins. The compensated “soft internal” is also often in sleeve-supported stance but holds the body up. It is clearly holding – by musculature – but the muscles themselves are not overdeveloped. Erect posture is easy because the fasciae don’t resist much. The impression of such structures is “dynamic” without efforting much.

The “hard internals” are far from normal. Muscles if adapted are well or over-developed because of a constantly increased demand on them. The muscles are sometimes amazingly soft, though, as if the passive resistance did not come from thick and hard fasciae but from a voluminous finely-spun web of relatively tender fibers. The compensated version so shows a competent musculature which performs well although with more effort but also more power than the “soft internal”. Knees and ankles may be tightly bound in to secure the joints, with muscles bulging between them. Collapsing seems to be partly a question of age, partly of the degree of hardness of the fascia. With progressing collapse the bodies and especially their lower girdles appear as “crushed”, the outer fascia losing tone.

With collapsed externals, the tissue of the lower girdle simply goes wide and the fasciae lose their tone. They often have a cement-like quality. The full picture of the external lower girdle collapse shows broad flat feet, wide and sunken malleoli which seem too much apart for the tarsus to fit in, shapeless and podgy knees, and a pelvis which is too broad and wide with the upper body collapsed into it. The compressional external lower girdle has no alternative to collapsing vertically, going wide and giving the impression of bone crushing heavily on bone inside. Internals collapse more into their folds which go apart and away from the Line in the sagittal plane. But occasionally one sees extremely collapsed externals with flat feet and a pelvis tilted completely posterior which are highly differentiated, possess tissue with good tone, and appear as very vital.

Internals which overcompensate tense their muscles to force the folds toward the Line, and as a result the tendons grow strong. Externals, where the bones are already more or less in line and have taken over a large part of the task of supporting the body from fascia, have nothing to gain from tightening the linear elements of tendons and ligaments. They get up and away from the ground by tightening the two-dimensional fascial layers, the sleeve. The lower girdle impresses as constricted circularly all along its length. In extreme cases the legs look thin as sticks so that one wonders how they should be able to hold up the body. Part of the answer is that muscles are not needed to support the structure because the bones and the fascial envelopes wrapped tightly around them are doing the job. The strongly constricted external pelvis often looks almost narrow and doesn’t provide the space necessary for the upper body to settle into it. The trunk seems to ride high on it with its peripheral tissue hanging down on the outside of the bony pelvis more or less. From behind, this pelvis presents an inverted triangular bony wall in the frontal plane of the body, the base being formed by the iliac crests, the apex by the narrow tuberosities.

At the foot, the over-compensating longitudinal arches also look different with internals and externals. With internals, the high arch seems to be built up by shortening and thickening of the plantar aponeurosis and perhaps the deep ligaments on the medial side of the sole of the foot. The heel is very varus and pulled forward medially. The lateral contour of the foot is convex, the ankle axis is slanted down laterally. The arch is higher medially than laterally, but the subtalar complex is often broad transversely. The lower leg when coming forward over the foot is thrown way out lateral. The external foot starts with a valgus calcaneus, and when the medial arch rises up, the foot actually often straightens out, the transverse axis through the ankle horizontalizing more. The lower leg is not thrown out much or seems to slip less often down medially. But the subtalar complex is narrow and high, it appears as a constricted block being compressed together and held up more by the ligaments internal to it than the more peripheral plantar ligaments and tendons.

Summing up, the internal and external lower girdles seem to differ in important ways in collapse as well as over-compensation. Internals have to check collapse tensionally, to which end they need muscles and strong and thick tendons. Externals collapse vertically, bone on bone, and where possible the segment with the bones inside goes wide: the pelvis, the ankles, the feet. But also those structures which show no collapse tolerance overcompensate differently. Internals again need muscles and the linear tensional elements of fascia, and when their connective tissue has a relatively soft quality and fascia is easily stretched, they succeed without too much damage. Externals tend to over-compensate by circular constriction of their fascial envelopes, the bones being compressed together as a consequence. Intention when -Rolfing so has to take regard of whether a tensional or a compressional system is to be integrated, and whether it is collapsed or over-compensated. Very generally formulated, over-compensated systems must be released first and let down to the ground while those collapsed must be built up from below to begin with.

The Upper Body

In the upper body there exists no possibility for going into a compressional regime comparable to the lower girdle. So at first the types fall into tensionally collapsed and tensionally over-compensated groups. They are assorted neatly as internals, which are more or less collapsed, and externals, which are usually over-compensated. It is very rare that one sees over-compensated internals, and if so, they usually only manage to raise their chest but not to straighten their spine much. When they do so, they mostly tilt the thorax back. This lifts the chest some, and by special effort this tendency can be carried farther a little. But the gain is at the cost of driving the LDH forward which in turn increases the lumbar lordosis.

Externals regularly show a spine straighter than normal. But this is often not homogenous for the whole spine. Internal “remnants” can then be found. Sometimes the lower lumbars show a marked lordosis with a small radius on top of which sits a straight thoracic spine. Other externals show a straight spine on a “steep” or nearly vertical sacrum which is topped by a kyphosis of the uppermost thoracics or an anterior shift of the cervicals.

Usually the two groups are separated clearly. The major reason for this relatively uniform trait of internals and externals seems to be the clear difference of the regimes of the lower girdles. For externals it is very easy to straighten their spine and raise the chest because the compressionally stable lower girdle offers a firm foundation against which the upper body can extend. When an integrated body imitates external posture, coming from internal, it feels almost “natural” and irresistible to also extend the upper body as soon as one glides into the compressionally supported stance. It even takes some concentration to go into external stance and leave the upper body collapsed on top of the lower girdle. In theory, normal stance of a normal structure with its horizontal and aligned pelvis should provide the conditions which permit the spine to be maximally long and extended. So both “flexion” and “extension disturbance” should result in a shorter, more curved spine.

Internals and symmetrical externals don’t possess the externals’ “bony buttress” below against which they could raise and extend the upper body. When they attempt to rise up, the largest part of the effort results in pushing the body down more into the tensional system below. The upward gain is small, and the toll musculature has to pay for containing the downward thrust is large. The mechanics can again be experienced easily by functional imitation or by imagining how one would stand up very erect on a heap of soft cushions.

Raising the upper body is harder for symmetrical externals than for internals. Their tensional elements in the lower girdle have less favorable leverage than those of internals for resisting the downward thrust. But they are also less in need of going up than internals because their C-curve or elongated thoracic kyphosis in combination with the tendency of leaning forward at the height of the cervico-thoracic junction opens their ribcage already well in the sagittal dimension.

For internals the muscular effort in the lower girdle is somewhat less, but the cost of the LDH and the lumbers being driven forward more reduces the possible gain considerably. But the internal locked-knee types present an interesting picture because the lower girdle has tensional as well as some compressional properties. From the tensional aspect the situation is worse than with regular internals, and so many of them show an extremely collapsed upper body. The spinal curves are maximally augmented, the chest is flat and drawn way down. The typical picture is that of very long-legged persons with a short upper body, which is however not wide or fat. Others manage to use the compressional qualities the lower girdle offers. They are marked by extension or slight hyperextension of the knees and the anterior shift of the pelvis. Typically, they don’t go all the way into relaxed sleeve-supported stance but keep the body closer to the Line by means of tensing the sleeve in front. They then succeed in raising the upper body against the lower girdle. They tend to a rather marked lordosis of the lower lumbars on top of which rests an extended spine and a high upper body.

All this makes it necessary to reexamine the proposition of the upper body being a tensional system not capable of going into a compressional regime(19). Although there are no bones which lend themselves readily to being lined up vertically in the middle as in the lower girdle, the spine of externals sometimes assumes a compressional character to some extent. The midline of externals is curved anterior convex, which puts the gravity center of the body relatively far back. The Line passing through it now comes to lie in the area of the vertebrae. They are so able to begin bearing weight, and in order to function properly as a compressional column the spine should be straight and approach vertical. Ideally the sacrum is steep, the lumbars are nearly straight, and the thoracics go deep, forward into the flesh.

Returning to the possible genesis of external structure again, there appears to be a sequence for the effort needed to produce the external lower girdle, spine, and ribcage. The primary posture and perhaps structure is assumed to be internal. Musculature limits the posterior shift and anterior tilt of the pelvis effected by gravity and set off by the primary imbalance of passive tissue tension of hip extensors and flexors. When the same musculature contracts more strongly, it drives the pelvis into an anterior shift and posterior tilt. Then at once it becomes superfluous because now gravity pushes the pelvis forward more and tilts it down in back. If the regime is competently compressional, other muscles regulate the lower girdle easily. The solid base for extension of the spine is laid.

To extend the spine, more effort is necessary. Gravity doesn’t take over from muscles at a certain point. The extensors of the spine must be active continuously and for a prolonged time, keeping the spine straight and forward close the Line. Only when the connective tissue rigidifies, adapting structurally to the posture, is part of the load taken from the muscles again. They need to work less because the spinal column is now structurally straight, kept that way by fascia. The system seems to be fairly stable because the load is mainly vertically down along the straight rigid spine. In contrast to this, the spine of internals is constantly pushed more into its curves, with occasionally the connective tissue giving in a little and settling again a little deeper in them.

The ribcage seems to require the most effort. Externals’ spine and lower girdle furnish a solid foundation, but because the weight line is close to the spine the ribcage is also fairly eccentric, out in front. This makes leverage less favorable. Muscles need to work resolutely for a long time until the ribcage stays up passively, being rigid in “inhalation”. Sometimes gravity’s effect can still be seen: by a group of ribs lagging on one side, the first two ribs sunk, or the sternum appearing to drag down.

All in all, form and function of the internal and external upper body are less clear than those of the lower girdle. This is in part because it is determined less gravitationally and has more freedom to choose various oaths of development, employing a wider range of methods.

Summary

The structural typology of internal/external derives from the functional phenomenon of craniosacral motion. This originates in a rhythmical lengthening and shortening of the “axial skeleton complex”. From there it spreads through the whole body. It does so uniformly the same way in every body as far as the direction of the moving parts is concerned which belongs to each of the two phases. Since it is completely independent from musculature this suggests that this bipolarity extending through the whole body is the reflection of a design of the shape of structure, especially of the fascial net, which is the same for everybody. It is argued that this is a much more important fact than the joints which fit into it.

Transformation of the functional phenomenon into a structural typology becomes possible where the two descriptive frameworks overlap. This is the case with the extremities where the two functional phases are separated by the space coordinates. Since arms and especially legs should be oriented exactly along them to be normal structurally, their internal or external deviation allows to define the respective structural types. This has nothing to do with how free craniosacral motion is to either side but is determined by on which side away from normal its “neutral zone” is found.

Rotation of the femora is then replaced by the pelvic tilt as the basic indicator for internal or external organization of the body. It also provides a sharp distinction because the structural norm is “no tilt”. And it places the theory firmly in the field of Structural Integration with its strong accent on the “horizontal pelvis”. First, it uses a “segment”, the most important one of them, which is a highly abstract and extremely relevant concept in the field while “bones” are relatively peripheral. Secondly, it connects the theory concretely to gravity. It distinguishes the internal and external type by whether the weight of the upper body falls in front or in back of the hip joint.

With this competes another mechanically relevant distinction, that of the sagittal pelvic shift which is an expression of an anterior or posterior convex midline. Because the internal and external characteristics through the body seem to follow more the tilt than the shift, tilt is confirmed as indicating the basic front-to-back pattern. The shift modifies this, however, and the four possible combinations of tilt and shift result in four types whose different mechanics are discussed.

A hypothesis for the genesis of internal and external structure is presented. It states that at birth some parts of the body lean toward internal, others toward external. With the infant standing up on its feet, gravity pushes the structure strongly into the internal pattern because of a primary shortness through the groin. Internals try to ease gravity’s effect by coming closer to the Line while externals choose a radical solution, perhaps based on the primary external features, which is very economical. The question of where conflict enters and what its function could be is posed several times but not answered. Such an answer seems to depend on a deeper understanding of structure but will have to be developed without a doubt along the lines of mechanics, gravity’s impact on structure and the way the body copes with it.

The internal/external system describes essentially structural front-to-back balance. This is the dimension which permits by far the most physiological mobility. A particular method is required to determine the structural state along a wide range of physiological motion. Opposed to this are left/right balance and structural rotations the state of which doesn’t follow normal function much; aberrations are “non-physiological”. Another issue, that of collapse/compensation which describes the tendency of a structure to give in to gravity or overreact against it, is laid over the internal/external system. It is not directly related to it, but the manifestation of collapse and overcompensation appears as different with internals and externals because of the different distribution of tensional and compressional traits between the two types.

Several alleys of inquiry opened up by the theory of internal and external structure have so been pointed out. Successful development depends entirely on the further working out of the internal/external system which has to take place concretely and specifically in the field of dynamic interaction between gravity and structure.

References

Sultan, Jan H: “Towards a Structural Logic”, Notes on S.I. 86/1

Upledger, John E., and Jon D. Vredevoogd: “Craniosacral Therapy”, Eastland Press, Chicago, 1983

Notes

1. The summary, follows Upledger’s description and includes a little experience in palpation. I have not used the method therapeutically however, and so this account must be considered somewhat superficial.

2. Meaning the point of view of the field of Structural Integration.

3. In integrated bodies joints have to bear little weight!

4. Embryology suggests a complementarily. Bones and joints seem to be laid out genetically but not in an absolute manner. Function is then necessary to shape the individual form in detail.

5. It must be remembered that “flexion” and “extension” refer exclusively to the behaviour of the spheno-basilar junction but no other joints in the body. The spine extends in “flexion” and flexes in “extension”!

6. It is tempting to “unify” the two theories by postulating that “truly” normal craniosacral motion is only achieved when structure is normal and vice versa. Reality does not seem to support this speculation however. Upledger shows two figures drawn from one person demonstrating “Whole Body Habitus of Chronic Craniosacral Flexion” and “Extension” (pp. 108, 110). External posture is shown convincingly, but the figure manages only marginally, with the distal extremities, to go into internal posture, the main part remaining external. This is with the assumption that the person posing has been treated amply by CST and possesses normal craniosacral motion. Structurally it is at the extreme end of external and therefore very far away from the Rolf norm.

7. The typology covers of course only a sector of the whole of structural reality

8. There is not really much contradiction between the two goals. Internal harmonization will generally lead to better balance if the main goal is not forgotten.

9. A layman’s speculation. But it should be remembered that this refers to the structural tendency of shifting the neutral point in one of the two directions, not to restrictions of craniosacral motion.

10. Within each group there will again be many options open for the body as to how it copes with the basic situation.

11. A clear and unequivocal method of determining the structural tilt is of course a prerequisite (cf. “The Tilt of the Pelvis”, Notes on S.I. 88/1). Also note that this choice does not only simplify matters but also raises a host of new questions!

12. The bones are considered ideally rigid here although some allowance probably needs to be made because they seem to possess some elastic deformability. “Ilium” usually stands for the whole “ilio-ischio-pubic complex” or the “innominate bone”. Movement in the pubic symphysis is disregarded.

13. Pure imagination is taxed here. It seems inevitable for understanding the situation to play with a sacrum and an ilium of a skeleton.

14. The term “fascia” designates all mechanically relevant dense connective tissue, here mainly the ligaments, the joint capsules, the periostium.

15. They do a little bit. The weight vector through the leg is more lateral with internals, more medial with externals.

16. The matter merits closer attention. It presumes that the varus heel is congruent with bow legs, the valgus one with X-legs. It is also not certain whether it is legitimate to take abduction and adduction of the femora as constitutive for internal and external legs instead of rotation.

17. “Balance” is a functional term here and meant in a broad sense. Everybody in whatever pose is “balanced” somehow or it would fall down. Opposed to that, Ida Rolf’s concept of structural balance introduces a value system. It fits into the first in the following way: if one body is able to hold an identical posture easier than another, its structural balance is better.

18. This is not exactly the same kind of support provided by normal structure!

19. The picture presented rests on experimental and experiential functional imitation of structural reality. The theory behind it is still tentative. But every Rolfer wanting to Rolf rationally experiments in these ways with his own body and that of others because otherwise he is unable to understand the mechanics of the human construction.