MUSCLES OF THE CHEST. 



599 



FIG. 193. 



num, and throwing the whole back towards the spine. It 

 will then be seen as a thin, broad muscle, covering the sides 

 of the chest, and situated between the ribs and the 

 scapula. 



It arises from the eight or nine upper ribs, by as many 

 fleshy digitations. The five lower interlock with the ex- 

 ternal oblique muscle, the upper one is short, thick, some- 

 what square, and is thought to resemble a distinct mus- 

 cle. Its fibres converge 

 and are inserted into th 

 whole base of the scap- 

 ula. 



Function. To draw 

 the shoulder forward, 

 and when the scapula 

 is fixed it can draw the 

 ribs outward, and aid 

 in inspiration. 



The intercostales (Fig. 

 193) occupy the spaces 

 between the ribs, are 

 twenty-two in number, 

 and divided into an ex- 

 ternal and internal set. 

 The external arise from 

 the transverse processes 

 of the dorsal vertebras, and from the inferior acute edge 

 of each rib, and then proceeding downward and for- 

 ward in fasciculi, are inserted into the superior smooth 

 border of the rib below to within a short distance of 

 the costal cartilage, the intervening space to the sternum 



FIG. 193 represents the Serratus Major Anticus Muscle. 1 Anterior portion 

 of cervical vertebrae. 2 Transverse process of the second cervical vertebra. 

 3 6 Scalenus anticus. 4 Levator anguli scapulae. 5 Lower edge of serratus 

 magnus. 7 Scalenus medius. 8 First rib. 9 Coraco-clavicular ligaments. 

 11 Clavicle. 12 Base of scapula, where the subscapularis is attached. 13 

 Upper portion of serratus magnus. 14 Lower portion of subscapularis. 15 15 

 Origin of serratus major anticus. 16 Internal intercostal muscles. 17 Ex- 

 ternal intercostals. 



