The quadratus femoris has a short, broad tendinous insertion on the quadrate tubercle on the intertrochanteric crest of the femur. The muscle belly is flat and quadrilateral, filling the space between the inferior gemellus superiorly and the adductor magnus inferiorly in the posterior hip. The insertion zone on the intertrochanteric crest is the site most commonly affected by ischiofemoral impingement-related oedema and tearing.
The quadratus femoris is the structure most reliably assessed in the diagnosis of ischiofemoral impingement on MRI, where muscle oedema (T2 hyperintensity within the quadratus femoris) is the primary imaging finding when the ischiofemoral space is narrowed. The tendon and muscle are compressed between the lesser trochanter and the ischial tuberosity in hip extension, adduction, and external rotation. Myofascial tears of the quadratus femoris at its ischial origin are also a recognised cause of posterior hip pain in athletes following forceful hip extension loading.
Compression of the quadratus femoris between the lesser trochanter and ischial tuberosity in a narrowed ischiofemoral space produces T2 muscle oedema visible on MRI, presenting as deep posterior hip pain in a snapping or clicking pattern, managed with activity modification, cortisone injection, and occasionally surgical decompression.
A proximal hamstring-equivalent injury at the ischial origin of the quadratus femoris following powerful hip extension and external rotation, producing acute posterior proximal thigh pain and sitting intolerance, managed conservatively with graded return to activity.
