| OCR Text |
Show 698 MR. F. G. PARSONS ON THE [June 16, The Extensor minimi digiti goes to the minimus and slightly to the annularis. The Extensor carpi ulnaris has the usual human attachments. The Supinator brevis consists of only one layer, which is superficial to the posterior interosseous nerve; its tendon forms tbe external lateral ligament of the elbow, and has an orbicular ligament attached to it. It is inserted into the upper quarter of the radius. The Extensor ossis metacarpl pollicis rises from the ulna as high as the lower margin of the lesser sigmoid cavity, also slightly from the radius. It has the usual insertion. There is no Extensor prlml lnternodii pollicis. The Extensor secundi lnternodii and Extensor Indicis form one muscle, which sends tendons to the pollex, index, and medius. The Palmaris brevis is large. The Abductor and Flexor brevis pollicis are small and united. There is no Opponens p>olllcls. The Abductor minimi digiti has already been described with the palmaris longus. The Flexor brevis and Opponens of the little finger are present, and rise from the pisiform bone and the sesamoid cartilage over it. The Intrinsic muscles of the hand are arranged in three layers, as described by Cunningham and Young. The superficial and deep layers correspond to Young's description of Petrogale, but the intermediate layer has more muscles in it. Muscles of the Trunk. The Serratus posticus is only represented by the anterior portion, corresponding to the serratus posticus superior of human anatomy ; it is well developed, and is inserted into the anterior ribs from the third to the ninth. The Erector splnae is very strongly developed, but presents nothing unusual. The External oblique rises from the third to the thirteenth ribs ; the marsupial bones are developed in it, while the external abdominal ring lies on the outer side of the middle of the marsupial bones. There are three tendinous intersections-one between the 11th and 12th ribs, one between the 12th and 13th, and one below the 13th. The Internal oblique is inserted into the last three ribs; dorsal to the lateral line of the body it is fleshy, while ventrally it becomes aponeurotic and blends with the transversalis. The Transversalis rises from the lower six ribs as well as the lumbar fascia and iliac crest. In the anterior two-thirds of the abdomen it passes deep to the rectus : in the posterior third it splits to enclose that muscle. The Bectus abdominis rises from the body, crest, aud pectineal line of the pubes behind the marsupial bone. It is inserted into the first rib by a very short flat tendon, as well as by its inner |
