Individual Variation.—The muscle is usually somewhat fused to the posteroproximal and anteroproximal fleshy corners of the underlying M. extensor iliofibularis.
M. Extensor Iliotibialis Anticus (M. sartorius), [Figs. 12], [13]
T. pallidicinctus
General Description and Relations.—Anteriormost muscle of thigh; long and strap-shaped; proximal part entirely anterior (adjacent) to M. extensor iliotibialis lateralis; posterior edge of middle part medial to latter muscle; distal part mostly medial to Mm. extensor iliotibialis lateralis and vastus medialis; proximal part aponeurotic, continuous posteriorly with anteroproximal aponeurosis of M. extensor iliotibialis lateralis; anterior edge of M. extensor iliotibialis lateralis bound by strong connective tissue to adjacent part of M. extensor iliotibialis anticus; some fusion of fibers (proximally) between these two muscles; anteroproximal corner of fleshy part of muscle sometimes fused to underlying anterior edge of ilium and fascia covering body wall musculature adjacent (anterior) to ilium.
Origin.—The muscle arises aponeurotically from the anterior part of the anterior iliac crest and (anteroproximal corner) from the anterior end of the median dorsal ridge.
Insertion.—The flat tendon, continuous posteriorly with the superficial tendon of M. femoritibialis internus, fuses to the tendon of M. vastus medialis, contributing superficially to the medial part of the patellar tendon, which attaches to the medial half of the rotular crest; most of the tendon is overlapped by the edge of M. gastrocnemius pars interna.
Innervation.—A branch of the anterior division of the femoral nerve gives twigs into the lateral surface of the posterior part.
Individual Variation.—In two legs, a twig from the anteriormost branch of the middle division of the femoral nerve anastomoses with the typical branch to M. extensor iliotibialis anticus.
T. cupido