A 44-year-old woman with right hip pain

Excerpt

The obturator internus muscle arises from the posterior surface of the obturator foramen. It then makes an acute angle, passing through the lesser sciatic foramen, and curving around the posterior aspect of the ischium and the hip joint capsule. The obturator internus tendon then receives tendinous fiber contributions from the superior and inferior gemelli, forming a functional unit, the triceps coxae, which inserts on the medial aspect of the greater trochanter. This functions primarily as a hip external rotator [1, 2]. The obturator internus bursa which is normally nondistended and non-visualized is located between the tendon and posterior ischium, and reduces frictional stress, facilitating smooth motion over that ridge [1‐3]. …