"The triceps coxae is the tricipital (three-headed) collection of 3 muscles in the posterior hip which act together on the hip, primarily to laterally rotate the extended thigh 1,2. It comprises (in order from superior to inferior) the superior gemellus, obturator internus and inferior gemellus muscles, lying between the piriformis muscle (superiorly) and quadratus femoris muscle (inferiorly) 3."