MYOLOGY OF THE OKNITIIOIUI VNCHUS. 



141 



expands upon the internal surface of the epicoracoid plate. The first 

 of these may be pectoralis minor; the second, subclavius? 



The cervico-scapular attachments are several, and rather compli- 

 cated. We have, first, two distinct muscles, both arising from the 

 spur of the atlas hypapophysis, but with separate scapular attach- 

 ments; each of these is a single belly. Then there are two planes of 

 digitate muscles, each arising from several cervical processes, and 

 with different scapular insertions. These last probably represent 

 duplicate levatores anguli scapulae proprii ; while the two first named 

 (also occurring in marsupials and other animals) are "protractores 

 scapulae." 



" Atlanto-acromialis." — A single thick stout muscle, lying superficial 

 and somewhat to the front, as well as on the side, of the neck, nearly 

 parallel with the omo-hyoicl, crossed above by the sterno-mastoicl, and 

 overlaid by the trapezius. With the tendinous origin above men- 

 tioned (hypapophysial process of atlas) it soon swells, to a large 

 belly, and is inserted fleshy into the antero-interior aspect of the scap- 

 ular crest, and thence in a line behind the episternal articulation as 

 far as the insertion of the omo-hyoicl. It draws the shoulder-blade 

 towards the head, and a little to the front. 



" Atlanto-seapularis." — Origin with the preceding, and in like man- 

 ner; and overlaid by it in the upper part of its course. It passes a 

 little more obliquely as it descends, lying upon the deeper muscles of 

 the back of the neck. It has somewhat the appearance of an enlarged 

 and distinct fasciculus of levator proper, with which it is inserted, 

 flashy, into the antero-internal surface and upper border of the scapu- 

 la near its apex. Action nearly the same as that of the foregoing, 

 but more oblique. 



Levatores anguli scapula;. — A double plane, with common digitate 

 origins, but separate insertions. Each numbers about 6 slips of origin 

 from the transverse processes of the first dorsal and all the cervical 

 vertebras except the atlas and axis ; the slips are separable nearly to 

 their insertion. The posterior, or internal plane lies directly upon 

 the muscles of the back of the neck ; it is quite flat, fan-shaped, and 

 converges from its broad origin to be inserted fleshy, into the pos- 

 terior extremity of the scapula, from the apex one-half«inch up the 

 blade. The digitations are all terete, and lie in the same plane. The 

 other muscle lies anterior to the last ; its digitations are broader and 

 flatter, enlarge as they pass to the scapula, and are packed obliquely 

 against each other. The lowermost slip does not reach the scapula, 

 ending in tendinous insertion into the next above ; the other five have 

 fleshy insertion into the antero-internal surface of the bone, chiefly 

 on a line near the edge of the crista. The action of both planes is 

 much the same; they draw the bone around to the front and upwards, 

 rotating it a little. 



