- Passive hip internal rotation and contraction of the obturator internus-gemellus complex is associated with ‘crimping’ of the sciatic nerve in the deep gluteal space.
BACKGROUND & OBJECTIVE
The sciatic nerve travels from within the pelvis into the deep gluteal space via the greater sciatic notch. Its pathway is most commonly beneath the piriformis (90%), with the second most common variation being through the piriformis muscle (7%) (1). The nerve then travels over the obturator internus and gemelli complex to exit the deep gluteal space via the ischial tunnel (between the ischium and the femur).
The sciatic nerve can get impinged or irritated by adjacent structures within the deep gluteal space (the ‘space’ beneath the gluteus maximus) which may result in pain at the site of local impingement and in the distribution of the sciatic nerve (true sciatica). The piriformis muscle, however, is only one of a number of structures that may impinge the sciatic nerve in the deep gluteal space, so while ‘piriformis syndrome’ has been grossly over diagnosed, sciatic nerve impingement or irritation in the deep gluteal space does occur and should not be overlooked in the differential diagnosis of buttock pain.
This study explored the relationship between the sciatic nerve and the deep hip external rotators in the deep gluteal space.
This new paper provides evidence that stretch or contraction of the obturator internus-gemelli complex will create some ‘crimping’ in the sciatic nerve at this level.
Sciatic nerve behavior was assessed in 58 healthy volunteers (30 males, mean age 20.4 ± 7.7 years), using real-time ultrasound and MATLAB software to quantify the change in shape of the nerve during hip actions. Participants were positioned in prone