I have a question in regards to the pectineus stretch. The muscle is divided into two different portions. The superior fiber is stretched into FA flexion, FA adduction and FA internal rotation. Does that mean the superior pectineus is a FA abductor, external rotator and FA extendor? For the inferior pectineus stretch, the stretch position is FA abduction, FA external rotation and FA flexion. Does that mean the inferior pectineus is a FA adductor and internal rotator?
There is general disagreement as to whether the pectineus rotates the thigh medially or laterally. The muscle runs from the pubis medially to a lateral distal attachment behind the femur which makes it look like a lateral rotator but because of the location of the AXIS of rotation of the femur it can appear that the muscle itself passes in front of the axis. In that case one could say that the muscle medially rotates the femur.
With flexion past 90 degrees the axis moves and we know that EMG activity increases for medial rotation. No matter what, it adducts and adduction power actually increases with flexion. Thus the picture on appendix page 86 in supine is focusing on the fibers that happen to laterally rotate the thigh. (if the patient happens to have any fibers that laterally rotate the thigh). The picture on 83 shows an ER stretch and that focuses on medial rotators.
Pectineus is a medial rotator on the whole with some debate on the ER component and no question on flexion and adduction. It would seem that the idea of flexing the hip (and doing ER or IR) is where the problem is since the pectineus is a hip flexor and flexing the hip would put it on slack. The best stretch therefore would then be page 84!
Reference Duchenne GB, Physiology of motion 1949
Kendall and McCreary, muscle testing and function, 1983 p 178
Travel and Simons, Myofascial Pain and Trigger Points Vol. 2 1993 p 239
-Michael Cantrell, MPT, PRC