General Description and Relations.—Small and triangular; ventral to posterior half of M. gluteus profundus; all but posteroventral corner deep to latter; posteromedial to M. iliacus, anterior to neck of femur, and dorsolateral (adjacent proximally) to M. psoas; proximal end notched at level of femoral notch for passage of anterodorsal division of femoral nerve; part anterior to femoral notch mainly tendinous; dorsal surface of proximal part somewhat fused to M. gluteus profundus, proximal accessory aponeurosis of M. extensor iliotibialis lateralis split into two sheets enclosing and fusing with M. iliotrochantericus medius, ultimately attaching to lateral edge of ilium in common with origin of latter muscle.
Origin.—The muscle arises from the ventrolateral surface of the ilium anterior to the acetabulum and posterior to the origin of M. iliacus; the anterior part attaches to the ventrolateral edge of the ilium and the posterior part attaches just above the ventral edge. The muscle is not attached to the concavity of the femoral notch (the origin is notched here). The part attaching anterior to the femoral notch is narrow, tendinous, and continuous anteriorly with the accessory aponeurosis of M. extensor iliotibialis lateralis (thus the anterior border of the muscle cannot be exactly delimited). The part attaching posterior to the femoral notch is wider and fleshy ([Fig. 20]A).
Insertion.—The short flat tendon attaches to the lateral surface of the distal end of the trochanter slightly anterior and immediately distal to the insertion of M. gluteus profundus; the attachment is proximal to the origin of M. vastus lateralis, anteroproximal to the insertion of M. piriformis, and several mm. proximal to the insertion of M. iliacus.
Innervation.—The small posterodorsal division of the femoral nerve penetrates the ventral surface.
Individual Variation.—On both sides of one specimen, the femoral notch is absent and the proximal end of the muscle is not notched; the proximal part is entirely fleshy and the anterior border is well defined ([Fig. 20]D).
T. cupido
Individual Variation.—The part attaching anterior to the femoral notch has a fleshy origin in one leg ([Fig. 20]B), but in another, no part attaches anterior to the femoral notch (thus the muscle is not notched). In one leg, the insertional tendon is strongly fused to, and continuous with, the ventral edge of the insertional tendon of M. gluteus profundus.
P. p. jamesi
Individual Variation.—The part attaching anterior to the femoral notch may be mainly or entirely fleshy. In one leg, the part attaching anterior to the femoral notch is entirely separate from, although overlapped by, the main part of the muscle for the entire length of the fleshy belly ([Fig. 20]C); both parts have a common insertional tendon.