112 THE OSTEOLOGY AND irSTOLOGY 



length ; it is not bound down and made to change its course by an aponeurotic loop ; nor is 

 it divided into two bellies by a central rounded tendon. But just where it passes the 

 sterno-mastoid an imperfect, flat, tendinous intersection may frequently be found. 



Besides the levator anguli scapulae proper and the omo-hyoid, which acts as such, 

 there are two other muscles, that proceed from the atlas to the scapula, — one to each 

 extremity of the latter — and draw the bone directly upward. Not knowing what names 

 they may have received, I shall describe them under the following ones : — 



" Atlanto-acromialis." — (Fig. 28, /*.) A stout, flattish ribbon, arising by a slight tendon 

 from the side of the ring and root of the transverse process of the atlas, passing down- 

 ward (gradually widening as it descends), and a little obliquely outward, to be inserted 

 fleshy into the root of the acromion and for half an inch along the under lip of the scap- 

 ular spine. It lies superficial in the greater part of its extent, being only covered by the 

 trapezius after passing the sterno- and cleido-mastoid. It pulls the scapula upward and 

 somewhat forward. 



" Atlanto-sccqndaris." — (Fig. 28, 5^.) Similar in general characters to the foregoing; 

 slenderer, more terete, longer, and with a more oblique line of traction. Its action upon 

 the scapula is almost identical with that of the omo-hyoid. It ai'ises from the apex and 

 posterior border of the transverse process of the atlas, and is inserted into the plane surface 

 at the posterior superior angle of the scapula ; generally between the edge of this bone and 

 the insertion of the omo-hyoid ; but the relative insertions of the two vary somewhat. 

 Teleologically, this muscle is a perfect "levator anguli scapulte " ; but it is not the muscle 

 so named in anthropotomy ; the latter existing, as we have seen, as the vertebral j^ortion 

 of the great plane of the serratus. 



PecioraUs major. — (Fig. 28, a.) The first part of the pectoral is of only moderate 

 bulk, although it arises from the whole length of the sternum, from ti]) of manubrium to 

 xiphoid. It takes origin from the median line of the surface of the bone, and conse- 

 quently in apposition with its fellow. Its upper corner overlies the insertion of the sterno- 

 mastoid ; but it has little, if any, origin from the clavicle. It is thinnest at its central 

 part, where it overlies the second pectoralis, — the latter seeming, as it were, to be developed 

 at the expense of this part of the major. It has an extensive insertion — into the whole 

 length of the outer edge of the bicipital groove, as low down as the aj)ex of the deltoid. 

 The lower free border is much longer than the upper, and is folded smoothly under in an 

 unusual manner ; just as the collar of a coat is folded over, without any twisting of the 

 fibres.' This inflected portion is entirely separated from the rest of the muscle, except, of 

 course along the line where it is turned under. It is the tendon of this inflected portion 

 that is chiefly connected with the tendon of the dermo-brachialis elsewhere described. 

 The upper portion of the muscle is much twisted. Those fibres that lie superficial at the 

 manubrium do not proceed along the clavicular border of the muscle to the top of the 

 bicipital groove, but are directed downward, so that their insertion is near the apex of the 

 deltoid ; while those that lie upon the deep surface opposite the second and third ribs, are 

 directed upward, soon emerging to the surface, and are inserted into the upper part of the 

 bicipital groove. The muscle has the usual action and lines of traction. 



Pectoralis major, its second division.-. — The second or middle pectoral is the smallest of 

 the three. It arises for about an inch and a half along the middle of the sternum, wholly 

 covered by the first division. The fibres converge to produce a fan-shaped muscle that 



