THE EXTERNAL MUSCLES OF THE HIP AND THIGH 277 



detaches a lamina which passes with the tendon of insertion of the superficial gluteus 

 to the external border of the femur. 



Relations — Externally, the skin and fascia; internally, the obliciuus aljdominis 

 externus, the iliacus, superficial gluteus, rectus femoris, and vastus externus, 

 branches of the circumflex iliac, ilio-lumbar, and iliaco-femoral arteries, and the 

 anterior gluteal nerve; anteriorly, the precrural lymph-glands. A considerable 

 quantity of connective tissue is found between the deep face of the muscle and the 

 abdominal wall. 



Blood-supply. — Circumflex iliac, ilio-lumbar, and iliaco-femoral arteries. 



Nerve-supply. — Anterior gluteal nerve. 



2. Gluteus superficialis (Figs. 178, 199) (Superficial gluteus; gluteus externus). — 

 This muscle lies behind and partly underneath the tensor fasciae lata^. It is 

 triangular and consists of an anterior and a posterior head united by the gluteal 

 fascia. 



Origin. — (1) The external angle and the adjacent part of the external border 

 of the ilium (anterior head); (2) the gluteal fascia (posterior head). 



Insertion. — The third (external) trochanter of the femur. 



Action. — To abduct the limb, flex the hip joint, and tense the gluteal fascia. 



Struct ure.^The anterior head of the muscle is not completely separable (ex- 

 cept artificially) from the tensor fasciae lata^. The attachment to the border of 

 the ilium is by means of an intermuscular septum, which passes beneath the thick 

 outer border of the gluteus medius. The posterior head arises from the deep face 

 of the gluteal fascia, and so indirectly from the dorsal sacro-iliac ligament. The 

 two heads unite and terminate on a strong flat tendon, which is inserted into the 

 edge of the third trochanter of the femur, beneath the biceps femoris. 



Relations. — Superficiallj', the skin, fascia, and biceps femoris; deeply, the 

 gluteus medius, iliacus, rectus femoris, and branches of the iliaco-femoral artery; 

 in front, the tensor fasciae latae; behind, the biceps femoris. 



Blood-supply.— Ghitesd and iliaco-femoral arteries. 



Nerve-supply. — Anterior gluteal nerve. 



3. Gluteus medius (Figs. 178, 179) (Middle gluteus; gluteus maximus). — 

 This is a very large muscle which covers the dorsal surface of the ilium and the 

 greater part of the lateral wall of the pelvis, and extends forward also on the lumbar 

 part of the longissimus. 



Origin. — (1) The aponeurosis of the longissimus, as far forward as the first 

 lumbar vertebra; (2) the gluteal or dorsal surface and internal and external 

 angles of the ilium; (3) the dorsal and lateral sacro-iliac and sacro-sciatic ligaments, 

 and the gluteal fascia. 



Insertion. — (1) The summit of the trochanter major of the femur; (2) the crest 

 below the trochanter; (3) the outer aspect of the trochanteric ridge. 



Action. — To extend the hip joint and abduct the limb. By its connection 

 with the longissimus a muscular mass is formed which is one of the chief factors in 

 rearing, kicking, and propulsion. 



Structure. — The anterior extremity of the muscle is relatively thin, and lies 

 in a depression on the surface of the longissimus, from the strong aponeurosis of 

 which the fibers take origin. The pelvic portion of the muscle is very voluminous, 

 and forms the bulk of the muscular mass which gives the haunch its rounded con- 

 tour. This part of the muscle is intersected by several tendinous sheets. One of 

 these is particularly distinct, and is attached to the gluteal line on the ilium. This 

 divides the muscle incompletely into superficial and deep strata. The superficial 

 part is inserted by a strong tendon into the summit of the great trochanter, and 

 by a pointed fleshy mass with a tendinous border into the trochanteric ridge. The 

 deep part (Gluteus accessorius) is smaller, and arises entirely from the ilium be- 

 tween the gluteal line and the external angle (Fig. 455). It has a strong flat tendon 



