BACK AND POSTERIOR CERVICAL REGION. 129 



The splenii muscles of the two sides do not meet along 

 the median line, but leave a space between them filled with 

 dense areolar tissue, the removal of which displays the 

 complexus muscle beneath. 



By dividing the splenius muscle the whole of the levator anguli 

 scapulae will be exposed. 



The LEVATOR ANGULI SCAPULAE arises by distinct slips 

 from the posterior tubercles of from three to five of the 

 superior cervical vertebrae, between the insertions of the 

 scalenus posticus and splenius muscles, which latter, with 

 the stern o-mastoid muscle, overlap a portion of it, and is 

 inserted by a fleshy tendon into the superior angle of the 

 scapula. It is sometimes split into several distinct mus- 

 cles, the divisions of its origin continuing down to its 

 insertion. 



The OMO-HYOID MUSCLE, connecting the scapula and 

 hyoid bone, consists of two bellies, an anterior and a 

 posterior. The anterior is described at p. 40. The pos- 

 terior belly is now seen. This portion arises from the 

 upper border of the scapula, near the supra-scapular 

 notch, and from the ligament which converts that notch 

 into a foramen ; it is thin and ribbon-like, and terminates 

 beneath the sterno-mastoid muscle in a tendon which 

 separates the muscle into its two halves, and which plays 

 through a loop formed by the deep cervical fascia. This 

 loop holds down the tendon so that the portion of the 

 muscle just described forms an obtuse angle with that part 

 inserted into the os hyoides. 



The supra-scapular nerve (p. 103) passes through the 

 supra-scapular notch beneath this muscle. The supra- 

 scapular artery (p. 58) also passes beneath this muscle, to 

 the supra-spinous fossa. The posterior scapular artery 

 (p. 59) passes under the levator anguli scapulae, and turns 

 downward along the base of the scapula, beneath the 

 rhomboid muscles, to supply the two surfaces of that 

 bone. 



In the interstices of the muscles which remain, and in 

 those which are to be made in separating them from each 

 other, numerous small arteries will be seen ; in the lumbar 

 region, they are posterior branches from the lumbar arteries ; 

 in the dorsal region, posterior branches from the intercostal 

 arteries ; and in the neck, posterior branches from the verte- 

 bral arteries, and from the profunda cervwis and super- 



