522 



DISSECTION OF THE BACK 



Levator 



anguli 



scapulae. 



Posterior 

 belly of the 

 omo-hyoid. 



Supra- 

 scapular 

 artery : 

 course to 

 shoulder. 



Supra- 

 scapular 



Transverse 



cervical 



artery 



divides into 



superficial 

 cervical and 



posterior 

 scapular. 



Accompany 

 ing veins. 



Nerve of 

 rhomboid 

 muscles. 



will be only incompletely displayed at present, but the following 

 points are to be made out (fig. 210, p. 576). 



1. The levator anguli scapula arises by four separate slips from 

 the posterior tubercles of the transverse processes of the upper four 

 cervical vertebrae, and in the case of the upper three slips, they 

 will be found to be attached immediately in front of those of the 

 splenius colli muscle. 



2. The posterior belly of the omo-hyoid passes from the upper 

 border of the scapula behind the notch, and from the ligament 

 converting the notch into a foramen, and forms a thin, riband like 

 muscle, which is directed forwards from beneath the trapezius 

 across the lower part of the neck, over the brachial plexus and the 

 suprascapular nerve, to the under surface of the sterno-mastoid, 

 where it ends in the intermediate tendon. 



The SUPRASCAPULAR ARTERY, a branch of the subclavian, is 

 directed outwards through the lower part of the neck to the upper 

 border of the scapula. It runs behind the clavicle, and crosses 

 the suprascapular ligament in front of the omo-hyoid muscle, to 

 enter the supraspinous fossa. 



The SUPRASCAPULAR NERVE is an offset of the fifth and sixth 

 cervical nerves in the brachial plexus and inclines downwards 

 beneath the omo-hyoid muscle to the notch in the upper border 

 of the scapula, through which it passes into the supraspinous 

 fossa. 



The TRANSVERSE CERVICAL ARTERY, also a branch of the sub- 

 clavian, has the same direction as the suprascapular, towards the 

 upper angle of the scapula, but it is higher than the clavicle. 

 Crossing the upper part of the space in which the sub-clavian 

 artery lies, it passes beneath the trapezius, and divides into 

 superficial cervical and posterior scapular branches. 



a. The superficial cervical branch is distributed chiefly to the 

 under surface of the trapezius, though it furnishes offsets to the 

 levator anguli scapulae and the cervical glands. 



6. The posterior scapular branch crosses under the levator anguli 

 scapulae, and descends along the base of the scapula beneath the 

 rhomboid muscles (p. 9). This branch arises very frequently 

 from the third part of the subclavian trunk. 



The suprascapular and transverse cervical veins have the same 

 course and branches as the arteries above described ; they open into 

 the external jugular, near its junction with the subclavian vein. 



NERVE TO THE RHOMBOID MUSCLES. This slender offset of the 

 fifth cervical nerve in the brachial plexus courses beneath the 

 elevator of the angle of the scapula, and is distributed to the rhorn- 

 boidei on their deep surface. Before its termination it supplies 

 one or two twigs to the elevator of the scapula. 



Dissection. On the third clay the rhomboid muscles will have 

 been reflected and the part will be free to the dissector of the head 

 and neck for two days, during which time he will examine the rest 

 of the parts described in this Section, as well as the spinal cord 

 and the contents of the spinal canal as set forth in Section IV. 



