Saturday, November 19, 2011

Fryette’s Laws

Fryette’s Laws?
Fryette's Laws, Lovett, motion coupling, osteopath, osteopathy, physiological motion, spinal kinematics, spinal motion In many institutions, and particularly in the USA, there seems to be tacit acceptance of the idea that the physiological motion of the spine can be reliably predicted and explained by reference to 'Fryette's Laws'. Given that nearly 100 years have elapsed since the ideas were originally formulated, why are they still being used?












Harrison M Fryette(1876-1960) was an early ‘pioneer’ osteopath who researched spinal motion over a number of years, with a seminal paper on the principles of spinal motion delivered to the American Osteopathic Association in 1918. However, it was some time before his ideas gained ground, until they were eventually revisited and relabelled as ‘laws’ as late as 1956 by T Edward Hall in the yearbook of the Osteopathic Institute of Applied Technique. The original principles were: Principle I: When the spine is in neutral, sidebending to one side will be accompanied by horizontal rotation to the opposite side. Principle II: When the spine is flexed or extended (non-neutral), sidebending to one side will be accompanied by rotation to the same side. a third principle was added in the 1940s by CR Nelson Principle III: When motion is introduced in one plane it will modify (reduce) motion in the other two planes.
Since the 1950s the osteopathic and chiropractic community have been enthusiastic in their adoption of these principles to the extent that they even appear in the Glossary of Osteopathic Terminology published by the American Osteopathic association (AOA) and questions based on these principles appear in state board examinations, set as current biomechanical theory and not as historical footnotes. Interestingly, the ‘laws’ as now published specifically exclude the cervical spine, as a result of a conflict between the original principles and the weight of current research findings.


On what basis were these ideas formulated?
Fryette drew heavily on earlier work conducted by Lovett in 19051. The research methodology consisted of cadaveric study and in vivo research via the application of gummed paper stickers to the spinous processes of a small number of student volunteers. The results were obtained by observing relative motion of these gummed paper stickers, and inferring as a consequence, the nature of the underlying spinal motion which had occurred.

Over the last century kinematic research has progressed from direct observation, cadaveric study, radiological analysis, cineradiology, CT, MRI, Steinman pins, implanted Gallium balls, to computer modelling. The more we are able to visualise and research living spinal motion, the more complex and unpredictable is the precise combination of individual joint rotation and translation for each region and segment. Rather than definitive ‘laws’ it appears that there are substantial individual and regional variations with, as yet, no accurate model for predicting all of the motion behaviour. With all this uncertainty why do some of us still persist in promoting a model for physiological motion based on work conducted over 100 years ago? The work of Fryette must be applauded for it’s longevity and insight, and celebrated as part of our osteopathic heritage and history, but the ‘laws’ can no longer be viewed as such, nor do they serve as a viable explanation of physiological motion behaviour.
Time to move on, and as Fryette2 himself emphasised: ‘No intelligent scientific spinal technic can be developed that is not based on an accurate understanding of the physiological movements of the spine’
1. Lovett RW (1905) The mechanism of the normal spine and its relation to scoliosis. Boston Med Surg J 13:349–358 ↩
2. Fryette H H; Principles of Osteopathic Technic, The Academy of Applied Osteopathy 1954 p.16
Fryette's Laws is a set of three laws pertaining to skeletal anatomy named after Harrison Fryette, D.O. It is defined as a set of guiding principles used by practitioners of osteopathic medicine to discriminate between dysfunctions in the axial skeleton. The first two laws solely apply to the lumbar and thoracic spinal regions, but the third applies to the entire vertebral column.[1] The first two laws were developed by Dr. Fryette in 1918, and the third was developed by C.R. Nelson, D.O in 1948.[2]
[edit] The three principles
1. Principle I: When the spine is in neutral, sidebending to one side will be accompanied by horizontal rotation to the opposite side. In type I somatic dysfunction this law can be seen when more than one vertebrae are out of alignment and cannot be returned to neutral by flexion or extension. The involved group of vertebrae demonstrates a coupled relationship between side bending and rotation. When the spine is neutral, side bending forces are applied to a group of typical vertebrae and the entire group will rotate toward the opposite side: the side of produced convexity [3] Extreme type I dysfunction is similar to scoliosis.
2. Principle II: When the spine is flexed or extended (non-neutral), sidebending to one side will be accompanied by rotation to the same side. In type II somatic dysfunction of the spine, this law can be seen when only one vertebrae is out of place and becomes much worse on flexion or extension. There will be rotation and sidebending in the same direction when this dysfunction is present.[4]
3. Principle III: When motion is introduced in one plane it will modify (reduce) motion in the other two planes.[5] Type III sums up the other two laws by stating dysfunction in one plane will negatively affect all other planes of motion.
[edit] References
1. ^ Fryette's Laws
2. ^ Robert G Savarese, John D Capobianco, James J Cox, JR. OMT Review, 3rd ed.
3. ^ Nelson, K and Glonek, T. Somatic Dysfunction in Osteopathic Family Medicine. Philadelphia: Lippincott Williams & Wilkins. p. 455.
4. ^ Greenman PE. Principles of Manual Medicine. Baltimore: Williams and Wilkins; 1989:58-60
5. ^ Greenman PE. Principles of Manual Medicine. Baltimore: Williams and Wilkins; 1989:58-60

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