THE MUSCLES. 145 



rior part). Use: to draw the scapula (particularly the inf. angle) 

 inwards, whereby the shoulder (humeral end) sinks. 



229. 6. Serratus posticus superior. 



Pos. : covered by the two preceding muscles, meeting anteriorly 

 in the m. scalen. post. Or. : Vv. seventh to the tenth proc. 

 spinos. Ins. : Costae second to the fifth (superior border, in the 

 neighbourhood of the angulus). Use : to draw the second to the 

 fifth rib upwards (m. inspirat.). 



230. 7. Serratus posticus inferior. 



Pos. : in the lumbar region, anterior to the m. latissim. dorsi, 

 united with its tendon. Or. : Vv. eighteenth to the twenty-second 

 proc. spinos. Ins.: Costse ninth to the twelfth (the inferior 

 border). Use: to draw the ninth to the twelfth ribs backwards 

 and downwards, and to fix them. 



Nerves : (first to the seventh) rr. posterr. nn. spinalium. 



231. C. Third layer. 



Pos. : in the posterior fossa of the vertebral column, between 

 proc. spinosi and transversi, or anguli costarum, separated from 

 the layers 1 and 2 byfasc. lumbo-dorsal. Or. : Proc. transversi. 



232. 1. Biventer cervicis. 



Pos. : covered above by diaphragm, below by splenii and 

 serrat. sup.; lies upon semi-spinal cervic. and complexus. Or.: 

 Vv. ninth to the fourteenth proc. transvers. (Apex). Ins.: Linea 

 semicircular, superior, (in the centre), united with m. complex, 

 cervic. The tendon between separates the superior and inferior 

 belly. Use : to draw the head backwards and rotate it a little ; 

 both extend it. 



233. 2. Complexus cervicis. 



Pos.: outside, close to the last m., covered by it, the splenii 

 and trachelo-mast. Or. : 1. Vv. eighth to the tenth proc. transv. 

 2. Vv. third to the seventh proc. obliqui. Ins. : below linea semi- 

 circular, superior, between trachelom. and the central line. Use: 

 to draw the head backwards and rotate it more strongly than the 

 last. 



234. 3. Trachelo-mastoideus. 



Pos.: external to the last, and before it; below covered by 

 splenii and lev. scapulas. Or. : 1 Vv. seventh to the eleventh 

 proc. transv. 2. Vv. fourth to the sixth proc. obliq. with seven 

 fasciculi. Ins. : Proc. Mastoid. (posterior part). Use : to draw 

 the head backwards and sideways. 

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