OCR Text |
Show 1879.] ANATOMY OF HYiENA CROCUTA. 101 vertebrae and terminates by a tendon which, blending with the fascia lata immediately above the knee-joint, is continuous with the biceps flexor cruris. The gluteus medius, as usual, exceeds in bulk the so-called maxi-mus. It arises from the external surface of the iliac bone and from the fascia covering the muscle, and is inserted into the outer surface of the great trochanter of the femur. Perfectly distinct, the gluteus minimus arises behind the last-mentioned muscle from the gluteal surface of the ilium and from the dorsum acetabuli. Its insertion is into the antero-external border of the great trochanter. The muscle is partially divisible into two, the posterior fibres passing to their insertion on a deeper plane than the anterior. A fourth gluteus (gluteus quartus) arises from the anterior border of the acetabulum over the reflected tendon of the rectus femoris, and is inserted into the middle of the anterior intertrochanteric line. This muscle appears to have been first described by Douglas in the Dog, under the name of " musculus parvus in articulatione femoris situs." Its existence in H. striata is noted by Meckel, and in the Civet by Macalister (" gluteus quintus ") and ourselves. The pyriformis has origin from the middle third of the ventral surface of the sacrum, and, running quite distinct and separate, is inserted into the great trochanter. Meckel found it in H. striata, but notes its absence in the Bear. It exists as a distinct muscle in the Civet. Obturator internus, which arises as usual, after emerging from the pelvic cavity, is accompanied to its termination by two well-marked and strong gemelli. The common insertion is into the trochanteric fossa. The obturator externus arises from the obturator-membrane and its bony boundary. It is also inserted into the trochanteric fossa of the femur. Quadratus femoris is from the outer border of the ischial tuberosity to the posterior border of the great trochanter. The above five muscles are similarly arranged in the Carnivora generally. Of the hamstring-muscles the semimembranosus is quite inseparable from the adductor magnus, in the description of which it is therefore included. To a more or less marked degree this union of the muscles is, according to Meckel, usual in Carnivores. He states, however, that in the Hyaena, Bear, Raccoon, and Coati the semimembranosus exists as a distinct muscle. W e have also found it quite separate throughout in Viverra, though in this animal Macalister states the contrary to be the case. This latter observer further notes its separate character in the Tayra. The semitendinosus arises from the ischial tuberosity, and is inserted into the internal surface of the shaft of the tibia near its superior extremity. Meckel found the insertion of this muscle to be lower in II. striata than is the case in II. crocuta; whilst in the Cynoids and Arctoids it is still lower down than in the Hyaena. |