586 DISSECTION OF THE BUTTOCK. 



into an impression across the outer surface of the great trochanter, extend- 

 ing from the tip behind to the root in front. 



The superficial surface is concealed in part by the gluteus iimximus; 

 and the deep is in contact with the glutens minimus, and the gluteal ves- 

 sels and nerve. The anterior border lies over the gluteus minimus, arid 

 is in contact with the tensor of the fascia lata. The posterior is contigu- 

 ous to the pyriformis, only the gluteal vessels intervening. A small bursa 

 is interposed between the tendon of insertion and the trochanter. 



Action. The whole muscle abducts the hanging femur; and the ante- 

 rior fibres rotate in the limb. In walking it is combined with the adduc- 

 tors in moving forwards the femur. 



Both limbs resting on the ground the muscles assist in fixing the pelvis. 

 In standing on one leg this gluteus will aid in balancing the pelvis on the 

 top of the femur. 



Dissection. When the gluteus medius is detached from the pelvis, and 

 partly separated from the gluteus minimus beneath, the gluteal vessels and 

 nerv r e will come into view. The two chief branches of the artery one 

 being near the iliac crest, and the other lower down are to be traced 

 through the fleshy fibres as the reflection of the gluteus is proceeded with ; 

 and the main part of the nerve is to be followed at the same time to the 

 tensor vaginas femoris muscle. The branches of the artery and nerve to 

 the gluteus medius will be cut in removing that muscle. 



The gluteal artery (fig. 200, a) is the largest branch of the internal 

 iliac (p. 513), and issues from the pelvis above the pyriform muscle. On 

 the dorsum of the hip bone it ends in offsets which supply the gluteal 

 muscles and the bone. Its named branches are superficial and deep: 



The superficial branch supplies offsets to the integuments, and some 

 deeper twigs over the sacrum ; it ends in the gluteus maximus, which it 

 penetrates on the under surface. 



The deep branch (fig. 201, a] is the continuation of the artery, and 

 subdivides into two pieces which run between the two smaller glutei. One 

 (b} (superior) courses along the origin of the gluteus minimus (supplying 

 mostly the medius) to the front of the iliac crest, where it anastomoses 

 with the ascending branch of the external circumflex artery. The other 

 portion (c) (inferior) is directed forwards over the middle of the smallest 

 gluteal muscle, witli the nerve, towards the anterior lower iliac spine 

 where it enters the tensor of the fascia lata, and communicates with the 

 external circumflex branch (p. 572): many offsets are furnished to the 

 gluteus minimus, and some pierce that muscle to supply the hip joint. 



Vein. The companion vein with the artery enters the pelvis, and ends 

 in the internal iliac vein. 



The superior gluteal nerve (fig. 201, J ) is a branch of the lumbo-sacral 

 cord (p. 495-6). It accompanies the gluteal artery, and divides into two 

 branches for the supply of the two smallest gluteal muscles : its lowest 

 branch terminates anteriorly in the tensor vaginae femoris, n. 



The GU THIS MINIMUS (fig. 201, c) is triangular in shape, and arises 

 from the dorsum of the hip bone between the superior and inferior curved 

 lines, extending backwards us far as the middle of the hip joint. Its ten- 

 don is inserted into an impression along the fore part of the great trochan- 

 ter, where it is united inferiorly with the gluteus medius: some fibres are 

 attached to the capsule of the hip joint. 



One surface is in contact with the gluteus medius, and the gluteal ves- 

 sels and nerve; the other with the hip bone, the hip joint, and the outer 



