THE GLUTEUS MAXIMUS. 



245 



the quadratus lumberum, and the brim of the pelvis, overlapping also the inner border of the 

 iliacus. The common tendon passes downwards in a deep groove between the anterior inferior 

 spine and the ilio-pectineal eminence, and lower down, between the tendon and the 

 -capsule of the hip, is a large synovial bursa which sometimes communicates with the cavity 

 -of the joint. 



Varieties. The iliacus minor or ilio-capsularls is a small detached portion of the iliacus 

 which is frequently present. It arises from the anterior inferior spine of the ilium, and is 



Fig. 249. SUPERFICIAL MUSCLES OF THE HIP AND THIGH, 

 SEEN FROM BEHIND. (Allen Thomson.) | 



1, gluteus medius, covered by the gluteal portion of the 

 fascia lata ; 2 ; gluteus maximus ; 2', lower part of the 

 fascial insertion of the gluteus maximus ; 3, vastus ex- 

 ternus ; 4, biceps flexor cruris ; 4', tendon of the biceps ; 

 5, 5', semitendinosus ; 6, 6, semimembranosus ; 7, 7', 

 gracilis ; 8, sartorius ; 9, adductor magnus ; 10, outer, 

 and 11, inner head of the gastrocnemius ; 12, placed in 

 the popliteal space, points to the origin of the plantaris* 



inserted into the lower part of the anterior intertro- 

 chanteric line of the femur, or into the ilio-femoral 

 ligament. 



The 2)soas parvus, a small muscle placed on the 

 surface of the psoas magnus, arises from the bodies 

 of the last dorsal and first lumbar vertebras, and from 

 the disc between them, and soon ends in a flat tendon, 

 which passes along the front and the inner side of 

 the psoas magnus, being incorporated with the iliac 

 fascia, and is inserted into the ilio-pectineal line and 

 eminence. This muscle, although it is well developed 

 and constant in animals generally, is very inconstant 

 in the human subject. Out of 450 bodies examined by 

 G-ruber it was absent on both sides in 183, on one side 

 only in 69. When present, it is liable to many changes 

 in the place of origin ; thus it may be connected only 

 with the first lumbar vertebra, or with the second 

 and the intervertebral substance above it, and it has 

 been observed to commence by two parts or heads 

 separated by an interval. 



The gluteus maximus is a very large and 

 coarsely fasciculated muscle, quadrilateral in 

 shape, which arises from the posterior fourth of 

 the iliac crest and from the rough surface of the 

 ilium between the crest and the posterior gluteal 

 line, from the back of the last two pieces of the 

 sacrum and the first three pieces of the coccyx, 

 from the great sacro-sciatic ligament, and be- 

 tween the sacrum and the ilium from the aponeu- 

 rosis of the erector spinae muscle. Thence it 

 passes downwards and outwards with parallel 

 fibres. The whole of the upper half of the 

 muscle, and the superficial fibres of the lower half are inserted into the strong 

 fascia on the outer side of the thigh ; the deeper and larger portion of the lower 

 half forms a flattened tendon which is attached to the gluteal ridge on the upper 

 third of the shaft of the femur. 



Relations. The gluteus maximus is superficial throughout. Its inner and lower part is 

 rendered especially prominent by the subjacent ischial tuberosity, and thus forms, with a con- 

 siderable quantity of overlying fat, the eminence of the buttock. Its lower border is crossed, 

 a little external to the middle, by the fold of the nates. The deep surface of the muscle rests 



R 2 



