Anatomical study of the obturator internus, gemelli and quadratus femoris muscles with special reference to their innervation

Abstract

The manner of innervation of the obturator internus, superior and inferior gemelli, and the quadratus femoris in humans (101 pelvic halves) and in rhesus monkeys (Macaca mulatta: 8 pelvic halves) were investigated. In most specimens, the inferior gemellus originated from the lateral surface of the ischial tuberosity and also from the medial surface (intrapelvic origin) just beneath the obturator internus and was covered by the falciform process of the sacrotuberous ligament. The superior gemellus was frequently innervated by the nerve to the obturator internus and the nerve to the quadratus femoris (60.4%), and the inferior gemellus was innervated by the obturator internus nerve in two specimens. The quadratus femoris nerve originated from more cranial segments than the obturator internus nerve, however these nerves had various communication patterns inside and outside the muscles. According to the intramuscular nerve distribution, in some specimens the branches to the superior gemellus from the quadratus femoris nerve extended to the inferior gemellus, and the branches to the inferior gemellus were distributed to the obturator internus. The present findings revealed that the positional relationships among the branches to the obturator internus and gemelli muscles are relatively constant, although the branching patterns and innervation patterns were varied. The various patterns and routes are considered to reflect the variability of the differentiation patterns of the anlage of the muscles. A possible schematic model of the positional relationships between the muscles and the nerves is Key words: obturator internus; quadratus femoris; gemelli muscles; innervation; sacral plexus; human gross anatomy; comparative morphologyThe obturator internus, quadratus femoris and gemelli are deep muscles of the hip joint. Several comparative anatomical studies have described the quadratus femoris (Cunningham, 1881;Wilson, 1888;Bardeen, 1907), however, few reports introduce the details of the obturator internus and gemelli muscles. Gräfenberg (1904) and Bardeen (1907) proposed that these muscles are derived from a common muscle anlage, and the obturator internus shifts to the intrapelvic space to cover the obturator foramen. Kikuchi (1987b) described that the superior gemellus is supplied not only by the nerve to the obturator internus (obturator internus nerve) but also by the nerve to the quadratus femoris (quadratus femoris nerve), and thus he proposed that the superior gemellus has two different origins. Recently, however, Shinohara (1995) proposed that the obturator internus and the two gemelli

Ultrasound-Guided Injection of the Intrapelvic Portion of the Obturator Internus in a Cadaver Model

“…11 The OI possesses unique anatomy among the hip short external rotators. 12 It originates from within the pelvis along the obturator foramen and membrane, exits through the lesser sciatic foramen by curving around the posterior ischium, and courses laterally deep to the sciatic nerve toward its common insertion with the gemelli on the medial side of the greater trochanter. 13 Similar to the piriformis, the OI functions primarily as a hip external rotator and may assist in abducting the flexed hip.…”

“…We performed B-mode, real-time ultrasonography using the ACCUVIX A30 system (Samsung, Seoul, South Korea) interfaced with a linear array transducer (5)(6)(7)(8)(9)(10)(11)(12). An investigator (S.C.L.)…”

Bilateral Absence of Gemelli Muscles: Case Report

“…Bardeen (1906) proposed that the obturator internus and gemelli muscles derive from a common outline, and then the obturator internus muscle moves toward the intrapelvic space to cover the obturator foramen. Aung et al (2001) indicated that during migration, the muscle bundles that extend medially to the ischiopubic ramus form the obturator internus muscle, and those which remain lateral to the ramus, form the gemelli muscles.…”

Persistent sciatica induced by quadratus femoris muscle tear and treated by surgical decompression: a case report

“…It acts as a hip external rotator and assists adduction [3,4]. The quadratus femoris muscle is innervated by the quadratus femoris nerve which rises from the ventral roots of the L4, L5 and S1 nerves in 79.4% of patients [5]. In adults, the myotendinous junction is the most vulnerable location for injury [6,7].…”