Cause #1: A loss of 10 degrees of anterior movement of the tibia over the talocrural joint.
Equinus is defined as limitation of ankle dorsiflexion to less than 10 degrees. Ten degrees of dorsiflexion is needed for normal gait and without it the function of the foot and associated structures of the lower limb and pelvis are radically altered. When this motion is absent, the foot compensates by adaptations from other parts; the mid-foot, transverse tarsal joint, the tibia, the femur and hip joints, and of course the pelvis. The patient will have a myriad of symptoms but the cause will be a loss of 10 degrees of dorsiflexion. Early heel off and a torsioning into abduction of the twisted osteoligamentous plate of the mid and forefoot is the first and most obvious sign. Because of the twisting effect of the lower limb the patient will appear to be a pronator (do not be fooled, this is nothing but an illusion) and will most likely be given an orthotic to correct the illusionary pronation. Please note that even after the orthotic device is in place the patient will not be able to squat, in fact, the orthotic will have converged the axes of the transverse tarsal joints and locked up the midfoot. This will cause a lifetime of misery to the patient. By this time the patient will be experiencing the effects of decreased mechanoreceptor activity and increased unchecked nociceptive input resulting in vasoconstriction, muscle spasm, and disuse (the ever perpetuating cycle of the sympathetic nervous system).
Cause #2: During the initial action of squatting, before the thighs reach the parallel, the ilii rotate posterior and the sacrum nutates anterior.
Remember that sacral nutation motion is best described as a triplanar motion. That is, three actions occurring through a central local at the same instant, in time resulting in movement in an anterior direction (sagittal plane, rotation on an axial plane, and tipping on a frontal plane). At a certain point, the sacrum will stop the nutation action (this is usually just prior to the thighs reaching a parallel position) and commence a counter-nutation movement. This action is the opposite in all respects to the nutation action. If this counter-nutation action is lost, the patient will compensate by lifting the heels from the floor contact position or by extreme forward flexion, even these attempts will not allow full squatting to occur.
The patient who presents with these actions being lost or fixated in time will, most likely as the result of long standing compensatory changes, be a chronic care patient. Chronic patients become victims of the subluxation complex and its primary causes. Chronic pain leads to a change or significant alteration in sleeping habits with deleterious effects on the quality and quantity of REM sleep; this state can or does create insomniacs which in turn produces depressed patients. A depressed patient generally is a patient that is presently inactive or lethargic by nature; loss of use creates a decrease in mechanoreceptor activity, and an increase in nociceptive firing, and once again we have the ever-perpetuating cycle of the subluxation complex.
The consequences are obvious. A patient who gets fed up with the cost and a lack of results tells no one of the marvelous benefits of chiropractic. A chronic patient with a lack of positive results tells everyone about the waste of time and money and the number of treatments received.
The bottom line is this: We in chiropractic need as many differential diagnostic tests as possible so that chiropractic can continue to get sick people better. MPI will continue to present to the profession many of these new and exciting tests and will incorporate these into the seminar series for 1994. Doctors, even if you took a Motion Palpation seminar three years ago, you will be surprised to see how much new material has been added and old obsolete material dropped. Yes, dropped! MPI will not keep old material if it is not valid or consistent with the research of the current times. How about you?
Keith Innes, DC
Dr. Innes will be teaching his next Extremities 1 (E1) seminar July 30-31 in Davenport, Iowa and his next Spine 2 (S2) seminar August 13-14 in Columbia, South Carolina. You may call 1-800-359-2289 to register.