Canadian Academy of Osteopathy Hamilton, Ontario. Canada.

What Are the Most Useful Osteopathic Tests? – Sacral Musings – Osteopathy Community

Robjohnston — Wed, 16 May 2012 19:46:00 +0000

What Are the Most Useful Osteopathic Tests?

Each of us will regularly use a number of tests when examining patients, each test having a part to play in providing a complete diagnosis. Tests also help to evaluate a patient’s response to treatment, as well as to serve as differential diagnosis during the initial consultation.

Some tests tend to be more reliable than others, and many tests in the teaching manuals are rarely used because they are forgotten in time.

Please think of some of the tests you like to use in practice.

• When and why do you use them?

• What is your rational in using one whilst excluding others?

• Do you conduct some tests all the time and with every patient?

I’ve listed three tests below that I regularly use with more or less every patient as they help me understand flexibility patterns, gait, specific areas of weakness and stress levels. I test them regularly and mark them as +/- and on an objective scale of 0-10 (high=excellent, low=poor)

I also ask the patient to provide their subjective input using the same criteria.

• Adam’s Test
This gives a simple visual test for pelvic symmetry and is used in functional or anatomical scoliosis assessment. In addition to the static test, which allows for the diagnosis of short leg conditions, the patient can be asked to conduct an active version of this test. Lateral flexion, flexion and rotation of the trunk on the pelvis may be a useful addition to diagnosing limited active range.

Adams test is a simple tool, which relies on visual parameters. Frequently it is helpful to assess the subject’s active ranges from a distance, as well as close up.

During the active assessment of flexion of the trunk on the pelvis, the assessor’s eyes are lined up horizontally with the Posterior Superior Iliac Spines, with their thumb positioned over the PSIS landmark.

A positive Adams is seen when the spinal column loses its vertical plane relative to the pelvis. The thoraco-lumbar spine produces a torsional deviation from the vertical. One side of the lumbar spine will produce a concavity, the other a convexity. The quadratus lumborum will be palpably shorter on the concave side.

In dynamic short leg conditions where the soft tissues are asymmetric due to factors such as fascial contraction, spasm or nerve irritation, the degree of asymmetry will change quickly over a few days when treatment commences.

In anatomical or fixed cases where contraction of tissues has occurred over time and with associated calcification and stenosis of adjacent joints, reversal is not anticipated.

The CAO Difference | Classical Osteopathy in Ontario

Robjohnston — Mon, 07 May 2012 02:23:34 +0000

I just returned from my first module in my second academic year at theCanadian Academy of Osteopathyand I want to share some thoughts. I want to share what I see as the standout qualities of the CAO.

The CAO is a school that is true to its stated purpose – to teach students the principles of Osteopathy so that they may work with any condition effectively and not rely on technique. This is extremely evident in the way that the classes flow between lectures and labs – there is a lecture on a certain subject that discusses the principles of a treatment (including relevant anatomy and physiology) and then it is straight to the tables where students are challenged to apply those principles to a treatment of their lab partner. During the lab all students are questioned and further taught about relevant anatomy and physiology. The principles of Osteopathy are always present and the information is woven together seamlessly. There is never a time when Osteopathy is not being taught. There is no segregation of topics, no time when we as students are dealing with Muscle Energy to the quadratus lumborum and nothing else – we as students are taught the principles of Muscle Energy, Strain – Counter-strain, Myofascial Release, Functional Technique, and every other “Osteopathic technique” and then challenged to create a “technique” using the principles from all different angles and positions. Through this process technique becomes irrelevant to a CAO student, the only thing left is treatment of Osteopathic lesions based on the principles.

Could Cranial motion be in fact an “ideomotor effect” ? – Sacral Musings – Osteopathy Community

Robjohnston — Mon, 30 Apr 2012 18:03:28 +0000

In a number of coutries, Osteopathy is becoming or close to be a healthcare profession. This should be considered an honor. But this rise to more responsability asks for a deeper introspection about what is based on belief from what is based on facts. This is especially true for the cranio-sacral concepts of Osteopathy.

Until recently, osteopaths were claiming that they could feel with their amazing palpation the movement of the Cerebro-spinal fluid that was pulsing in the cranium. Later on a few researches have shown that was impossible. Quick, hurry a new theory ! Electro-magnetic pulse? Venous pulse? Contractibility of the dura mater ? Quantum healing? The only research showing some effect of cranial therapy on a body’s rythm was done in 2002 on 23 participants. It shows an effect a smoothening of the Traube-Hering-Mayer pulsations with a cranial approach. This is a bit weak to validate the existency of cranial motion. More than 5 researches were done to see if 2 osteopaths were feeling the same rythm on the same patient. None of them were conclusive! Whilst all the evidences seem to show that cranial motion is non-existent, nonetheless a lot of osteopaths still practice and believe in cranio-sacral therapy and its concept.

Osteopaths do feel a movement, Are you saying that thousands of osteopaths are having palpatory hallucinations ?

Yes and no…

Pain – Is It All In Your Head? | Classical Osteopathy in Ontario

Robjohnston — Tue, 17 Apr 2012 18:07:20 +0000

I came across this interesting video onSacral Musings. The basic premise is that pain is not the reality of a situation – it is the efferent modulating response to protect the human organism from stimulus that may be harmful. Watch the video and then read on…

As a student at the Canadian Academy of Osteopathy this concept is often highlighted by Vice Principal Brandon Stevens when he says: pain is born at the dorsal horn but it isn’t pain until it reaches the brain. What we have is a situation where afferent stimulus is assigned meaning in the cerebrum based on past experiences with the stimulus and then the efferent response reflects the meaning that has been assigned to the stimulus (as is evidenced in Mr. Moseley’s explanation of being bitten by the snake). From this it can be inferred that the job of pain is simply protective as it is not indicative of the reality of the stimulus.

What might this mean for an Osteopathic Operator? Stimulus that has created pain for a patient in the past will create efferent responses that will likely be dominated by the sympathetic nervous system. If an Operator does not monitor ALL barriers (including mental – these are palpable in the body and are displayed through efferent responses) then treatment will not have the intended goals. Some pain/discomfort is entirely social – a good example would be the removal of clothing for treatment is not a comfortable thing for most Canadians so I leave my patients fully clothed to avoid the discomfort that may get in the way of an effective treatment. Patients present with different life stories and those will alter the way that an Operator is able to effectively touch them which is one of the reasons that reliance on technique is problematic – if my patient has had an issue with the way their neck has been handled in the past I can not just use standard cervical “techniques”, I will have to understand how else I might effectively use the principles of Osteopathic treatment to work with the mechanics of this individual patient’s cervical spine without scaring them to a point that I am unable to treat them. Every Operator will approach this from different angles and that is fine as long as the patient is provided with effective results.

The Ninth Thoracic Vertebra

Robjohnston — Sun, 08 Apr 2012 22:37:00 +0000

The ninth dorsal segment is next on the list for my Marion Clark exploration. A lesion of the ninth dorsal is most often an anterior displacement or a torsion according to Clark. Considering the rotational and flexion bias of the dorsal vertebrae this should be fairly clear. From a pathology point of view the anterior displacement is more likely problematic due to the decrease of size in the intervertebral foramina.

For most people, a lesion of the ninth dorsal segment is most likely to affect thegreater splanchic nerve (due to some quirks of anatomy it may also affect the lesser splanchic nerve for some individuals). As a result of influence over the greater splanchic nerve effects will be seen in the: stomach, spleen, gall bladder, liver, kidney, small intestine, the ascending and transverse colon. It is also important to consider the connections to the celiac ganglia and adrenal medulla via the greater splanchic nerve. Also keep in mind that the greater splanchic nerve passes through the diaphragm on the way to the abdomen making it highly unlikely that any treatment aimed at the ninth dorsal segment or the greater splanchic nerve would be complete without addressing the diaphragm locally as well as neurologically (via thephrenic nerve). According to Clark the most affected viscus is the kidney when the ninth dorsal segment is in lesion.

As always, depending on the nature of the lesion in the ninth dorsal segment there will be excitation or inhibition to neurologically connected areas. If the intervertbral foramina is lessened bilaterally or unilaterally then the lesion will be inhibitory where the foramina is lessened.

Through my present investigation of Clark’s work I am currently very much in the mindset that basing much of my treatment on mechanical principles is the most effective way to provide physiological modulation. I am positive that my viewpoint will continue to evolve and I look forward to it. At the moment I am of the opinion that most results through Osteopathic treatment arise from the balancing of mechanical function – not only is there a display of localized alteration in physiological movement there is also alteration in structurally related physiology. This should be self evident through the principles of Osteopathy – my current point is that most treatment need not be localized to viscera or other specific structures. To provide an engineering reference (similar to what Dr. Still seemed fond of) there is no point fixing the steering wheel if you have a bent chassis – straighten the chassis and then see if the steering wheel needs to be fixed.

History of Osteopathy – DR. ANDREW TAYLOR STILL.

Robjohnston — Wed, 04 Apr 2012 16:03:53 +0000

DR. ANDREW TAYLOR STILL.

The talent of success is nothing more than doing what you can do well and doing well whatever you do, without a thought of fame. - Longfellow.

The History of Osteopathy to the present time is inseparably connected with the life of Dr. Andrew Taylor Still. Osteopathy had its conception in the fertile brain of that one man, was developed by his careful judgment, grew into favor through his determined purpose, and was placed upon a solid footing by his sagacity. All the elements that have contributed to the advancement of Osteopathy are to be found in the very nature of its founder. And many of the elements that make Dr. Still what he has been and still is, are the results of the environments of his life.

No artifice can make of a man that for which nature did not endow him. But the natural and artificial surroundings of a young man often determine the particular direction of his life. This is preeminently true of the subject of this chapter. Dr. Oliver Wendell Holmes once said that the time to begin to train a child is with its grandparents. So the only way to become really familiar with a man is to make the acquaintance of his ancestors.

DR. A. T. STILL’S PATERNAL ANCESTORS.

Dr. Still’s great-grandfather on his father’s side came to Buncombe County, North Carolina. Whence, is not positively known, but it seems from one account that he and five brothers came from England.

Dr. Still’s grandfather, Boat Still, was born in North Carolina. He was one of eight brothers, and was said to be the “runt” of the family, weighing two hundred and eleven pounds. He married Mary Lyda, a Dutch woman. She was a good frontier’s woman, and is known to have killed the fiercest of wild beasts with her rifle. They raised a family of fifteen children, eight daughters and seven sons, five of whom were doctors.

One of the sons, Dr. Abram Still, was Dr. A. T. Still’s father. He was born in Buncombe County, North Carolina, about 1797. The family removed to Tennessee where Abram Still was ordained as a preacher in Holston Conference, Methodist Episcopal Church, and sent as a circuit rider to Tazewell County in the southwestern part of Virginia. While there he married Martha P. Moore, daughter of the third James Moore mentioned below. There Dr. E. C. Still, Andrew’s oldest brother, was born, January 15, 1824. They soon removed to Lee County, Virginia, where James M., Andrew T., Thomas C., and Jane were born. Thence they moved to New Market, Jefferson County, Tennessee, where John W. was born. Thomas C. Still says his father was at one time Parson Brownlow’s family physician at Knoxville, Tenn. No wonder he became an ardent abolitionist. All the sons were doctors and strong antislavery men. The following is a continuation of the story of the family, as related to the author by Dr. E. C. Still at his home in Macon, Missouri, November 29, 1944:

“Then my father, wanting to get to a new country where he could get land cheap, took a transfer from Holston Conference, M. E. Church, to the Missouri Conference of the same. Moving from there and landing in Macon County, Missouri, near Bloomington, May 2, 1837, he bought a claim at once, at which place Mary M. Still was born. After remaining three years he bought another claim in Schuyler County, moved there and took possession of it, at which place my sister, Marovia M. Still, was born. We remained there five or six years, moving back again to the same place in Macon County, about 1845, at which place my youngest sister, Cassander, was born. We remained in that neighborhood in Macon County for some years, during which time the division of the Methodist Church took place. My father remaining with the old, or Methodist Episcopal Church rendered him unpopular in a political sense. Being what they called a free soiler, at that time, rendering it dangerous to his life, he asked the Methodist Conference for an appointment where he would be in less danger. He was sent to Kansas Territory to the Shawnee Mission about 1852, to the same Indians that massacred the Moore family, they having been transferred by the United States Government. He found there the same names among the Indians as in the east, and some of them remembered the tradition of my great-grandmother’s tragic death.

“I remained in Macon County and practiced medicine from about 1845 to about 1882. About that time I became interested with my brother, A. T. Still, in the treatment of disease without medicine, afterwards named Osteopathy. Following that practice for some years, assisting my brother in Osteopathy up to the time of McKinley’s second election, November, 1990, I was taken down sick at that time and have not practiced since, though I have good health now. I was in service during the Rebellion.

“At first the general impression was that we were switched off or crazy. The doctors called Andrew a damned old jackass, and suggested sending him a block of hay. I had obtained their confidence by being a good surgeon. They rather pitied me for siding with the crazy old jackass. The preachers said it was all the works of the devil. Doctors said it was too damned a fraud to be noticed. We were ostracized from any kind of fraternal feeling.”

While in Missouri, Abram Still served the M. E. Church as circuit rider and presiding elder, and at the same time administered to the sick. Thos. C. Still says of his father “He would often have to stop in the fall season to attend the sick. His universal practice was to keep close by his Bible in his saddle-bags, a well filled wallet of medicines in sections of canes as battles were likely to break. Thus armed his main aim was for the comfort of both soul and body.”

HIS MATERNAL ANCESTORS.

The earliest authentic history of Dr. Still’s ancestors on his mother’s side is found in a most interesting little volume entitled “The Captives of Abb’s Valley,” written “by a son of Mary Moore,” who was a cousin of Dr. Still’s mother, and published about 1854. It is found in many Presbyterian Sunday-school libraries, records facts that are indeed stranger than fiction, and contains material that appeals to man’s love of adventure as well as his devotion to religion.

James Moore, Dr. Still’s great-great-grandfather, came from Ireland about the year 1726, and settled in Chester County, Pennsylvania. He was of Scotch descent, his ancestors having emigrated to northern Ireland from Scotland. He married Jane Walker, a descendant of the Rutherfords, of Scotland. They had five sons and five daughters, from whom are descended many of the first families of Virginia and Kentucky. He died about 1792, and his wife, some two years ago. Their sixth child and second son bore the name James Moore also. He married Martha Poage. After several years they moved into Abb’s Valley, Tazewell County, Virginia. The fight for possession of that country had long been contested by the Shawnee and the Cherokee Indians, and many a bloody battle had been fought between them, and many depredations upon the early settlers had been committed by both of them.

This second James Moore, Dr. Still’s great-grandfather, was a man of no ordinary ability. He became a captain in the militia and led a company in General Green’s army in the hard fought battle of Guilford Court House, N. C., March 15, 1781. “It has been said of him that he was never known to lose his presence of mind in any emergency in which he was placed.”

On the morning of July 14, 1786, after the members of the Moore family had begun their respective employments, Black Wolf, at the head of thirty or forty Shawnee warriors, attacked the family. Captain Moore ran to the house, but found the door barred by those who had taken refuge in it. Running past the house, he halted only a moment in climbing the yard fence, when he was pierced with seven balls. He ran about forty paces, fell, and was immediately tomahawked and scalped. Three of the children were also killed, and the others, with their mother, were captured. The Indians started with their captives to near where Detroit now stands. One boy being unable to stand the fatigue of the journey, was killed the second day, and the babe being fretful, had its brains dashed out against a tree. Before they reached their destination, Mrs. Moore and a daughter were also put to death. Dr. E. C. Still relates the following tradition concerning his great-grandmother’s death:

“Tradition obtained by my grandfather from the Shawnee squaws, says that owing to her complainings of the loss of her child, they took her to the stake, cutting off, slicing, broiling, and eating her breasts before her; sticking her full of fine splinters and burning her at the stake, at a French trading post called Detroit. The above tradition was handed down to me through my mother, who obtained it from her father, James Moore, who had been captured by the Shawnee Indians and kept with them seven years. We don’t know the tradition to be history, but my grandfather and my mother believed it to be true; he obtained it from the Shawnee squaws, who thought a great deal of my grandfather and protected him when the braves were drinking and carousing. The squaws obtained it from the braves.”

The Ninth Thoracic Vertebra

Robjohnston — Thu, 29 Mar 2012 19:09:33 +0000

THE PRACTICAL MAGNETIC HEALER IN PLAIN ENGLISH GIVING THE SYMPTOMS AND CAUSES OF DIFFERENT DISEASES

Robjohnston — Mon, 19 Mar 2012 01:53:56 +0000

In giving a description of the different manipulations, the author makes no claims as to their specific value as a therapeutic, but simply states that they were used as a means of transit, conveying the suggestion to the forces within the patient, which it is claimed, brings the patient back to health. In formulating the symptoms and causes of the diseases herein contained the author has taken great care in quoting from the best diagnosticians both in Europe and America, which is considered to be the best authority obtainable on this subject. He takes pleasure in naming the following as his authority on the subject above referred to, and will be considered authentic. Dr. Faulkner, Carmichael, Pierce, Root, Riley, Fowler, and others, making the diagnosis for practical purposes entirely reliable.

REMEDY FOR RHEUMATISM

The so-called involuntary forces (by the medical fraternity) are, with reference to the science of magnetic healing, called subjective forces, subjective faculties of the mind, or better yet, THE SUBJECTIVE MIND. In treating all diseases the operator has to deal, ultimately, with the Subjective Mind of his patient, and of course the most convenient way to reach it, is through the objective or conscious mind. It seems to be the duty of the conscious mind to stand guard over the subjective mind, and to best reach it you will find it necessary to enter into a compact or an agreement with the conscious mind to let your suggestions pass to the subjective mind, thus impressing it with the work of restoring your patient to health.

The office of the subjective mind seems to be to work out the impressions given to it by the conscious mind of the patient or operator. The impressions are worked out with neatness and dispatch, PROVIDED the subjective mind has the material at hand with which to do the work. What would you expect your engineer to do first? Should you order him to start the machinery? Would you not secure the necessary material to create heat and generate steam? Your (engineer) subjective mind must have (fuel) oxygen, to create heat, and water to generate (steam) blood, lymph and secretions. The whole body must also be lubricated, like unto a much complicated piece of machinery, every bearing, however small, must be lubricated. Water furnishes the basis for all liquids within animal bodies, and is the only vehicle on which all solid bodies are conveyed from one part of the body to another, or from the internal to the external. All worn out or dead cells are conveyed to the exterior on this vehicle. You will then readily see the importance, of, at first, securing the necessary material preparatory to rebuilding your physical structure. The above also applies to keeping your house, the body, in order. Then let cold winter come, winds may blow, snows may fall, it is all the same to you, for when you hear the gentle tapping from the outside, you will be found upon the throne as undisputed ruler over your little kingdom of health and happiness. It is the writer’s intention in other comments to discuss the best means of reaching the subjective faculities, as applied in treating diseases of various characters, especially those involving the excretory functions.

HOW TO TREAT A BAD CASE OF RHEUMATISM

Have your patient recline on your operating table in a comfortable position, closing his eyes and relaxing every muscle. The operator should tell his patient to direct his mind to the aching joint and hold it there during the treatment. If you find the patient inclined to talk or let his mind wander from the seat of the trouble you should be more positive in order to get him interested in the treatment sufficiently to create a desire on his part to have you discontinue the treatment for the present, at least. It will be observed that your patient will think not of his former sufferings from his rheumatism, but think only of improved feelings over the pains endured before treatment. If your patient complains of severe treatment, tell him that you would not hurt him for the world if it were not absolutely necessary, and that the next treatment will not need to be so severe. You will find that after the first treatment your patient will be on the lookout for developments in the region of the rheumatism, and you will have no trouble in holding your patient’s mind just where you want it. You will find it beneficial to stir up the muscular tissue, producing revulsion, thus aiding the mind in the work of restoring your patient to health. After you have finished the treatment, tell your patient to take a few full and deep breaths, after which have him open his eyes, at the same time tell him that he will feel better, and in almost every case your patient will feel much improved. During the treatment you should keep your thoughts on the work in hand, with a feeling of confidence in your ability to cure your patient, and that he can and must get well. It is well that you express those thoughts to your patient at times that seems most suited, in your judgment, for such expressions.

If you should at any time have a patient with semi-acute rheumatism in either one of the lower limbs, necesssitating the use of crutches, treat the seat of pain with your hot hands, made so by rubbing them briskly together, holding them on the diseased part until perspiration starts, thus you have forced into activity the lymphatic circulation, the pain is thereby subdued, and your patient has changed his course and is now convalescing. Now, is the time to act, look your patient squarely in the eyes and tell him to get down off the table and walk, that he can surely do so, without a doubt, that you know just what you are talking about, tell him to try it, that he can surely do it, and you will witness the seemingly impossible performance of “taking a man off of his crutches in twenty minutes.”

There are many cases of chronic rheumatism that can be immediately relieved and permanently cured, by at first giving a local treatment to the parts afflicted, then look after the stomach and kidneys, with a view of establishing a normal condition in these organs; after you have succeeded in this, you can then look after the stiff joints and painful parts of your patient’s body, the purpose of which is to establish a normal circulation throughout. You can now give your patient the necessary instructions. You will find in nine out of every ten of your patients that he has been eating about one-fourth more than his stomach could digest, you will also find that he has been drinking very little water, or perhaps none at all, thus depriving his stomach of the necessary liquids to digest the food, in this case the food remains indigested and if it passes out of the stomach at all it does so in an indigested condition, after the period in which the contents of the stomach should have passed into the duodenum, fermentation has set in and decomposition is now going on, the absorbent glands are now taking up this poison and conveying it to the blood. The system has no particular use for this substance and in carrying it throughout the body as a burden to the blood, it finds lodgment in the joints or between the muscular tissues, upon which it has a granulating effect upon the tender membrane, causing irritation and inflammation or acute inflammatory rheumatism. Now the next thing for the operator to know, is how to relieve and permanently cure his patient.

The first thing is to increase the venous circulation. To do this, you should use the necessary manipulations to force the blood toward the heart, after this, you should bring about conditions to reestablish perfect digestion. Your patient’s stomach is like unto a faithful work horse that has been overloaded. It has refused to work, not having been able to do the work assigned to it; to overcome this obstacle, lighten the burden, give it a rest, and it will gradually resume its former function.

There is one very important point that should not be overlooked in this matter, and that is the material of which secretions are made, in order to have an abundance of lubricating fluid, by which you can properly lubricate all the bearings throughout your whole body, thus permitting the different organs to act in harmony with each other, in the absence of which health cannot exist.

Taking then into consideration this state of affairs, your patient suffers intensely through the acute stage and in time settles down into a chronic invalid, suffering intensely all kinds of pains.

The next thing to be looked after is the circulation. In order to equalize the circulation, you should get your patient to help you, which he can do by deep breathing, thus assisting the heart in forcing the blood through the capillaries, then back again to the lungs, where the principle impurities are cast out of the blood; in this exercise there are several points gained, such as developing the lungs, aiding the stomach in its work of digestion, forcing the secretions into the colon and producing the peristaltic motion so essential in breaking up constipation, assisting the lymphatic circulation, and generally aids all functional activity.

Compare osteopathy and chiropractic – Sacral Musings – Video

Robjohnston — Fri, 16 Mar 2012 13:33:55 +0000

People often compare osteopathy and chiropractic. This historical footage might supply some visually appealing historical perspective. One of Andrew Taylor Still, the founder of osteopathy treating, and another of BJ Palmer, the son of chiropractic founder DD Palmer treating.

BJ Palmer:

Andrew Taylor Still:

Still In The Junction: The Eleventh Thoracic Vertebra | Classical Osteopathy in Ontario

Robjohnston — Mon, 12 Mar 2012 13:10:56 +0000

I haven’t forgotten my Osteopathic terminology – the only time I will use the term thoracic in place of dorsal is in the title of my posts! It is now time to continue up the column to the eleventh dorsal segment.

The eleventh dorsal segment is part of the thoraco-lumbar junction with the twelfth dorsal segment and thefirst lumbar segment. As such the eleventh dorsal segment shares characteristics with a lumbar vertebra (such as a more posteriorly directed spinous process, a larger vertebral body, smaller transverse processes). The eleventh rib articulates directly with the body of the eleventh dorsal segment thus providing a greater degree of movement when compared to the dorsal segments above it.

The visceral structures that are most often affected by a lesion of the eleventh dorsal segment are: small intestine, vermiform appendix, cecum, ovaries, testes, kidney, spleen, ureter, prostate, epididymus, Fallopian tubes, and suprarenal capsules. Much of these connections are made via the lesser splanchic nerve as well as connections via the renal plexus. As with any other segment the effects of a lesion will be determined by whether they are inhibitory or excitatory to the nerve controlling the area in question. Generally, as has been noted before, a flexion/increase in size of the intervertebral foramen (whether unilateral or bilateral) will be excitatory while extension/decrease in size of the intervertebral foramen (unilateral or bilateral) is usually inhibitory.