518 



THE MUSCLES AND FASCIA 



to one another, and collected into large bundles, separated by deep cellular 

 intervals. It arises from the superior curved line of the ilium, and the portion 

 of bone, including the crest, immediately above and behind it; from the posterior 

 surface of the lower part of the sacrum, the side of the coccyx, the aponeurosis 

 of the Erector spinae muscle, the great sacrosciatic ligament, and the fascia cover- 

 ing the Gluteus medius. The fibres are directed obliquely downward and outward ; 

 those forming the upper and large portion of the muscle, together with the super- 

 ficial fibres of the lower portion, terminate in a thick tendinous lamina, which 

 passes across the great trochanter and is inserted into the fascia lata covering the 



outer side of the thigh; the deeper fibres of 

 the lower portion of the muscles are inserted 

 into the rough line leading from the great 

 trochanter to the linea aspera between the 

 Vastus externus and Adductor magnus. 

 1. Dissection of 



gluteal region. Relations. By its superficial surface, with a thin 



fascia, which separates it from the subcutaneous 

 tissue; by its deep surface, from above dowmvard, 

 w T ith the ilium, sacrum, coccyx, and great sacrosciatic 

 ligament, part of the Gluteus medius, Pyriformis, 

 Gemelli, Obturator internus, Quadratus femoris, the 

 tuberosity of the ischium, great trochanter, the origin 

 of the Biceps femoris, Semitendinosus, Semimem- 

 branosus, and Adductor magnus muscles. The 

 superficial part of the gluteal artery reaches the deep 

 surface of the muscle by passing between the Pyrifor- 

 mis and the Gluteus medius; the sciatic and internal 

 pudic vessels and nerves and muscular branches from 

 the sacral plexus issue from the pelvis below the 

 Pyriformis. The first perforating artery and the 

 terminal branches of the internal circumflex artery 

 are also found under cover of the muscle. Its tipper 

 border is thin, and connected with the Gluteus medius 

 by the fascia lata. Its lower border is free and promi- 

 nent. 



Several synovia! bursae are found in relation with 

 this muscle. One of these (bursa trochanterica in. 

 r/lutaei maxinii}, of large size, and generally multiloc- 

 ular, separates it from the great trochanter. A second 

 (bursa ischiadica m. glutaei ma.vimi), often wanting, is 

 situated on the tuberosity of the ischium. A third 

 bursa is found between the tendon of this muscle and 

 the Vastus externus. Two or three small bursse 

 (bursae glutaeofemorales) are placed between the ten-r 

 don of the muscle and that of the Vastus externus. 



Dissection. Divide the Gluteus maximus near its 

 origin by a vertical incision carried from its upper to 

 its lower border; a cellular interval will be exposed, 

 separating it from the Gluteus medius and External 



rotator muscles beneath. The upper portion of the muscle is to be altogether detached, and 

 the lower portion turned outward; the loose areolar tissue filling up the interspace between 

 the trochanter major and tuberosity of the ischium being removed, the parts already enumerated 

 as exposed by the removal of this muscle will be seen. 



The Gluteus medius (m. glutaeus medius} (Fig. 387) is a broad, thick, radiating 

 muscle, situated on the outer surface of the pelvis. Its posterior third is covered 

 by the Gluteus maximus; its anterior two-thirds by the fascia lata, which separates 

 it from the integument. It arises from the outer surface of the ilium, between 

 the superior and middle curved lines, and from the outer lip of that portion of 

 the crest which is between them; it also arises from the dense fascia, the gluteal 

 aponeurosis, covering its outer surface. The fibres converge to a strong flattened 



3. Back of thigh. 



2. Popliteal space. 



4- Back of leg. 



5. Sole of foot. 



FIG. 386. Dissection of lower extremity. 

 Posterior view. 



