202 



THE SKELETON. 



THE SCAPULA. 



The Scapula forms the back part of the shoulder. It is a large flat bone, 

 triangular in shape, situated at the posterior aspect and side of the thorax, be- 

 tween the first and eighth ribs, its posterior border or base being about an inch 

 from, and nearly parallel with, the spinous processes of the vertebrae. It pre- 

 sents for examination two surfaces, three borders, and three angles. 



The anterior surface, or venter (Fig. 151), presents a broad concavity, the sub- 

 scapular fossa. It is marked, in the posterior two-thirds, by several oblique 



Fig. 151. Left Scapula. Anterior Surface, or Venter. 



ridges, which pass from behind obliquely outwards and upwards, the anterior 

 third being smooth. The oblique ridges give attachment to the tendinous in- 

 tersections, and the surfaces between them, to the fleshy fibres, of the Sub- 

 scapularis muscle. The anterior third of the fossa, which is smooth, is covered 

 by, but does not afford attachment to, the fibres of this muscle. This surface 

 is separated from the posterior border by a smooth triangular margin at the 

 superior and inferior angles, and in the interval between these by a narrow 



