THE HEAD AND NECK, POSTERIOR. 131 



Besides the muscular branches, the artery supplies the 

 integument of the back of the head ; the cutaneous 

 branches are accompanied by the cutaneous filaments from 



the occipital nerve. 



DISSECTION. 



Divide the trapezius half an inch from its attachment to the occipital bone, 

 and along the median line (to meet the one dissecting it from below) , and 

 turn the muscle downward and outward over the shoulder. 



Splenius Capitis et Colli. Figs. 76 and 77. 



Origin. From the lower half of the ligamentum nuchae, 

 the spinous processes of the seventh cervical, and five or 

 six upper dorsal vertebrae and the supraspinous ligament. 



Insertion. By two portions. The " capitis " portion, 

 into the outer third of the superior curved line of the 

 occipital bone and the mastoid process of the temporal 

 bone. The " colli " portion, into the posterior tubercles 

 of the three or four upper cervical vertebrae. 



Nerve Supply. The external branches of the posterior 

 divisions of the cervical nerves. 



Action. When both act, they extend the head and 

 neck ; if one acts, it rotates and flexes the head and 

 neck laterally, to the same side. 

 Levator Anguli Scapulae. See Upper Extremity. 

 Posterior Scapular Artery. See page 113. 



DISSECTION. 



Sever the splenius along its cranial and spinal attachment and turn the 

 muscle inward. 



Trachelomastoid. 



Origin. From the articular processes of the three or 

 four lower cervical and the transverse processes of the 

 four or five upper dorsal vertebrae. 



Insertion. Into the mastoid process of the temporal 

 bone. 



