The themes of our first column “Carotid Sinus Syndrome and Carotid Sinus Syncope” have been chosen in honor of a dear and understandably unnamed colleague and in honor of the swift sympathetic response the above named syncope caused in her body.
First a brief quotation to define the problem: “Strong pressure on the neck over the bifurcations of the carotids in the human being can excite the baro receptors of the carotid sinuses, causing the arterial pressure to fall as much as 20mm Hg in a normal person. In some older persons, particularly after calcified arteriosclerotic plaques have developed in the carotid arteries, pressure on the carotid sinuses often causes such strong responses that the heart stops completely, or at least the arterial pressure falls drastically. Even tight collars can cause the arterial pressure to fall low enough to cause fainting in these persons, an effect called Carotid Sinus Syncope. Fortunately, when the reflex causes the heart to stop, the ventricles usually “escape” from vagal inhibition in approximately 7 to 10 seconds and begin to beat with their own intrinsic rhythm. However, occasionally the ventricles fail to escape, and the patient dies of cardiac arrest.”
The client my colleague was Rolfing was a strong young man, and she had not exactly aimed for his carotid sinuses, but after she had put strong bilateral pressure on the areas of the origin of his sternocleido mastoidei, he said that he felt a little faint. After she had moved her hands down to the insertions, the fellow fainted.
Lets review the anatomy: the carotid sinuses are located laterally and slightly inferiorly to the superior margin of the thyroid cartilage posterior to the sternocleido-mastoideus (see illustrations). A very slight palpatory pressure alongside the medial edge of the sterno-cleido-mastoideus about an inch inferior to the mandible will reveal the carotid pulse and your fingers will then be right on the sinus. This does not mean that when our hands are one inch or two away from the actual site we can exert strong pressure. Pressure aimed at the connective tissue of the muscles is O.K. but it should never compress the artery and it should certainly never be done bilaterally. Furthermore, exerting pressure anywhere along the carotid arteries can be hazardous. This includes pressure from anterior, inferior, posterior directions and even pressure indirectly created by extreme rotation. The carotid sinuses being baro receptors, sense pressure changes, they do not sense where the pressure comes from. So let’s not pressure them, they are high-strung. Always remember the old Rolfing maxim: “Stay off the thompers!”
It is not quite accurate that arteriosclerotic plaque only occurs in the arteries of the elderly. It has been found during autopsy in the carotid arteries of service men in their twenties. Considering the nutritional habits of many first world people, we should forget about this myth. It is true that the elderly are more at risk, and should they let you know in their first interview that they have been diagnosed with arteriosclerosis (which you would have asked about, I’m sure) it would be essential to have their neck X-rayed by a friendly MD. or Chiropractor (I hope all of us have a minimum of those up our sleeves). X-rays of the neck show plaquing clearly to a radiologist. The other important question to ask is whether your client ever faints for no obvious reason, which could indicate -compromised vasculature.
The quoted information about the carotid sinus was taken from Guyton: Textbook of Medical Physiology, chapter 21, under Rapidly Acting Nervous Mechanisms for Arterial Pressure Control. The illustrations are borrowed from Kahle, Leonhardt, Platzer: Anatomy I. Chapter: Topographic Anatomy of the Head and Neck.
Questions can be addressed to my office. This is the first of a regular column to appear in Rolf Lines. The articles will be printed so that the page can be removed and kept in a file for ready reference, if you like.