Fryette's Laws

Fryette's Laws is a set of laws developed by Harrison Fryette, M.D., D.O. It is defined as set of guiding principles developed by Harrison Fryette, DO, and used by practitioners of osteopathic medicine to discriminate between dysfunctions in the axial skeleton. Three kinds of patterns are classified. The first two solely apply to the lumbar and thoracic spinal regions, and the third applies to the spinal region. [http://medical-dictionary.thefreedictionary.com/Fryette%27s+Laws">Fryette's Laws] . The first two laws were developed by Dr. Fryette and the third was developed by C.R. Nelson, D.O.

The three laws are:Law I = when the spine is in neutral (easy normal), sidebending to one side will be accompanied by rotation to the opposite side.Law II = When the spine is flexed or extended (non-neutral), sidebending to one side will be accompanied by rotation to the same side.Law III = When motion is introduced in one plane it will modify (reduce) motion in the other two planes. [Greenman PE. Principles of Manual Medicine. Baltimore: Williams and Wilkins; 1989:58-60]

In type I somatic dysfunction this law can be seen when more than one vertebrae is out of alignment and it will not be relieved by flexion or extension. The involved gorup of vertebrae demonstrates a coupled relation shipt 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 side of produced convexity [Nelson, K and Glonek, T. Somatic Dysfunction in Osteopathic Family Medicine. Philadelphia: Lippincott Williams & Wilkins. p. 455.] Extreme type I dysfunction is similar to scoliosis.

In type II somatic dysfunction of the spine, this law can be seen when only one vertebrae is out of place and will get much worse on flexion or extension. There will be rotation and sidebending in the same directions when this dysfunction is present [Greenman PE. Principles of Manual Medicine. Baltimore: Williams and Wilkins; 1989:58-60] .

Type III sums up the other two laws that states that if there is dysfunction in one plane all other planes of movement are also affected due to this dysfunction.

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