OCR Text |
Show 698 MR. T. MANNERS-SMITH O N THE [Dec. 4, and are inserted into the radius at the junction of the upper middle thirds. Between the two heads of origin a muscle is inserted which is probably the pectoralis minor. Only one head is present in Echidna (Mivart, loc. cit.). Fig. 1. M U S C L E S O F A R M . a. Brachialis anticus. /3. Triceps, y. Infra-spinatus. S. Epicoraco-brachialis. e. Deltoid. Coraco-brachialis.-Two portions of the typical coraco-brachialis are present. A longer superficial portion, arising in conjunction with inner (larger) head of biceps from sternal portion of coracoid; it is inserted into the bar of bone bridging over the well-marked supra-condyloid foramen. The deeper portion arises from coracoid and whole of epicoracoid, just beloAv and in front of glenoid cavity; it is inserted into the upper third of the humerus. The two portions are entirely distinct, the tendon of latissimus dorsi separating them from below ; both parts are supplied by a branch from the median nerve. The first portion only is called by Coues coraco-brachialis ; the second he describes as epicoraco-brachialis ; the same two portions are found in Echidna (Mivart, loc. cit.). There is a distinct epicoraco-brachialis, but in addition two portions of the typical coraco-brachialis are present, as described above. Brachialis anticus.-Arises from humerus, its origin extending as high as the head of the bone. The muscle is inserted into the upper fourth of the shaft of the ulna. Triceps.-This is a very large, strong muscle, consisting of four |