414 MUSCLES AND FASCIJE. 



subcutaneous tissue. By its deep surface, from above downwards, with the 

 ilium, sacrum, coccyx, and great sacro-sciatic ligament, part of the Gluteus 

 Medius, Pyriformis, Gemelli, Obturator Internus, Quadratus Femoris, the tube- 

 rosity of the ischium, great trochanter, the origin of the Biceps, Semitendinosus, 

 Semimernbranosus, and Adductor Magnus muscles. The gluteal vessels and 

 superior gluteal nerve are seen issuing from the pelvis above the Pyriformis 

 muscle, the ischiatic and internal pudic vessels and nerves, and the nerve to 

 the Obturator Internus muscle below it. Its upper border is thin, and connected 

 with the Gluteus Medius by the fascia lata. Its loiver border, free and promi- 

 nent, forms the fold of the nates, and is directed towards the perineum. 



Dissection. Now 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 outwards ; 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 seeu. 



The Gluteus Medius is a broad, thick, radiated 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 integu- 

 ment. 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 covering its anterior part. 

 The fibres converge to a strong flattened tendon, which is inserted into the 

 oblique line which traverses the outer surface of the great trochanter. A 

 synovial bursa separates the tendon of the muscle from the surface of the 

 trochanter in front of its insertion. 



delations. By its superficial surface, with the Gluteus Maximus behind, the 

 Tensor Vagina3 Femoris, and deep fascia in front. By its deep surface, with the 

 Gluteus Minimus and the gluteal vessels and superior gluteal nerve. Its an- 

 terior border is blended with the Gluteus Minimus. Its- posterior border lies 

 parallel with the Pyriformis, the gluteal vessels intervening. 



This muscle should now be divided near its insertion and turned upwards, when the Gluteus 

 Minimus will be exposed. 



The Gluteus Minimus, the smallest of the three glutei, is placed immediately 

 beneath the preceding. It is fan-shaped, arising from the outer surface of the 

 ilium, between the middle and inferior curved lines, and behind, from the mar- 

 gin of the great sacro-sciatic notch ; the fibres converge to the deep surface of 

 a radiated aponeurosis, which, terminating in a tendon, is inserted into an im- 

 pression on the anterior border of the great trochanter. A synovial bursa is 

 interposed between the tendon and the great trochanter. 



Relations. By its superficial surface, with the Gluteus Medius, and the gluteal 

 vessels and superior gluteal nerve. By its deep surface, with the ilium, the 

 reflected tendon of the Rectus Femoris, and ca'psular ligament of the hip-joint. 

 Its anterior margin is blended with the Gluteus Medius. Its posterior margin is 

 often joined with the tendon of the Pyriformis. 



The Pyriformis is a flat muscle, pyramidal in shape, lying almost parallel 

 with the lower margin of the Gluteus Minimus. It is situated partly within 

 the pelvis at its posterior part, and partly at the back of the hip-joint. It arises 

 from the front of the sacrum by three fleshy digitations, attached to the portions 

 of bone between the first, second, third, and fourth anterior sacral foramina, 

 and also from the grooves leading from the foramina : a few fibres also arise 

 from the margin of the great sacro-sciatic foramen, and from the anterior surface 

 of the great sacro-sciatic ligament. The muscle passes out of the pelvis through 

 the great sacro-sciatic foramen, the upper part of which it fills, and is inserted 

 by a rounded tendon into the upper border of the great trochanter, being gene- 

 rally blended with the tendon of the Obturator Internus. 



Relations. By its anterior surface, within the pelvis, with the rectum (espe- 



