494 MUSCLES ON POSTERIOR NECK AND BACK. 



edges of the four or five superior ribs, by as many tendons, 

 and forms a small fleshy belly, which is inserted by three 

 or four tendons into the transverse processes of the fourth, 

 fifth, and sixth cervical vertebras. Function. To draw the 

 neck backward and to one side. 



Transversalis colli (or cervicis) appears to be a continua- 

 tion of the longissimus dorsi, and is about the same size 

 with the last. It arises from the transverse processes of 

 the four or six superior dorsal, and is inserted by small ten- 

 dons into the transverse processes of the four or five lower 

 cervical vertebrae. Function. To draw the neck backward. 



The tracJielo-mastoideus , situated between the last and the 

 complexus, seems also to be a continuation of the longissi- 

 mus dorsi, upward. It arises tendinous from the transverse 

 processes of the three or four superior dorsal, and four or 

 five inferior cervical, and forms a very delicate and slender 

 muscle, which ascends to be inserted into the posterior part 

 of the mastoid process, beneath the splenius. Function. To 

 bend the head and neck backward and to rotate to one side. 



The complexus is seen between the upper heads of the 

 diverging splenii, and is a large and thick muscle. The 

 tendinous matter noticed in its substance, gives it the com- 

 plex appearance, whence its name is derived. It arises 

 from the transverse and oblique processes of the five or 

 seven superior dorsal, and three or four inferior cervical, 

 and is inserted into the occipital bone, along with its fel- 

 low, on either side of the median line, between the two 

 semicircular ridges. Function. To draw the head back. 



Fifth layer, (Fig. 151.) Dissection. Kemove the muscles 

 of the fourth layer, by dividing them in their middle and 

 reflecting them to either end. This layer consists of the 

 following five muscles : 



The rectus capitis rjosticus major, is of a triangular shape, 

 arises, tendinous and fleshy, from the spinous process of 

 the vertebra dentata, and is inserted broad into the inferior 

 transverse ridge of the os-occipitis. Function. To draw 

 the head back and rotate it on the atlas. 



The rectus capitis posticus minor, like the last, is also 



