DISSECTION OF THE BACK 59 



and a lower part by a transverse cut at the level of the angle 

 between the clavicle and the spine of the scapula, and verify the 

 attachment of the upper part to the posterior border of the lateral 

 third of the clavicle and the attachment of the lower part to the 

 medial border of the acromion and the upper margin of the 

 posterior border of the spine of the scapula. Next clean away the 

 fat in the area exposed and display the posterior belly of the 

 omo-hyoid muscle, the transverse scapular artery, the supra- 

 scapular nerve and the fascia over the supraspinatus. The supra- 

 spinatus covers the scapula between the spine and the upper 

 border of the bone. The posterior belly of the omo-hyoid is 

 attached to the lateral part of the upper border. The transverse 

 scapular artery crosses the upper border immediately lateral to 

 the omo-hyoid, resting on the superior transverse ligament, 

 which passes from the upper border to the coracoid process, 

 and separates the transverse scapular artery from the supra- 

 scapular nerve. 



When the structures mentioned have been defined, draw the 

 scapula well over the edge of the block which supports the 

 thorax, and examine the muscles which attach the vertebral 

 border of the scapula to the vertebral column ; they are (i) 

 the levalor scapulae, (2) the rhomboideus minor, (3) the rhom- 

 boideus major. The levator scapulae is attached to the scapula 

 from the medial angle of the scapula to the flattened apex of the 

 spine of the scapula, the rhomboideus minor opposite the 

 flattened apex and the rhomboideus major from the flattened 

 apex to the inferior angle. 



Cut through the fascia between the levator scapulas and the 

 rhomboideus minor about one inch medial to the scapula, and 

 find the dorsalis scapulas nerve which supplies the rhomboid 

 muscles and the descending branch of the transverse cervical 

 artery which accompanies it. (Fig. 26, p. 52.) These structures 

 will be traced to their terminations when the levator scapulas and 

 the rhomboids are reflected. 



M. Omo-hyoideus, Arteria Transversa Scapulae (O.T. 

 Suprascapular Artery) et N. Suprascapularis. The slender 

 posterior belly of the omo-hyoid muscle will be seen to arise from 

 the upper margin of the scapula, immediately medial to the 

 scapular notch. It derives fibres also from the ligament 

 which bridges across this notch. It is supplied by a twig 

 from a nerve loop in the neck called the ansa hypoglossi. 

 The transverse scapular artery will be noticed to enter the 

 supraspinous fossa of the scapula by passing over the superior 

 transverse scapular ligament, whilst the suprascapular nerve 

 proceeds into the fossa under cover of that ligament (Fig. 38). 



Mm. Bhomboidei. The two rhomboid muscles constitute 

 a thin quadrangular sheet of muscular fibres, .which extends 

 from the spinous processes of the vertebrae to the vertebral 

 margin of the scapula. 



The rhomboideus minor is a narrow, ribbon -like fleshy 



