SCAPULAR VESSELS AND NERVES. 9 



Action. From the direction of their fibres both rhomboidei will J e by 

 draw the base of the scapula upwards and backwards, so as to 

 depress the acromion. In combination with the trapezius they with others, 

 carry the scapula directly back ; and acting with the serratus 

 inagnus, they serve to fix the scapula. 



The OMOHYOID MUSCLE consists of two fleshy bellies, anterior Posterior 

 and posterior, which are united by an intervening tendon. Only omohyoid : 

 the posterior half is now seen. 



The muscle arises from the upper border of the scapula behind origin 

 the notch, and from the ligament converting the notch into a foramen, nation ; 

 The fibres form a thin, riband-like muscle, which is directed for- 

 wards across the lower part of the neck, and ends anteriorly in a 

 tendon beneath the sterno-mastoid muscle. This belly is partly relations, 

 placed beneath the trapezius, and is partly superficial in the posterior 

 triangular space of the neck, where it lies above the clavicle and 

 the subclavian artery, and crosses the brachial plexus and the 

 suprascapular nerve. 



Action. The use of the muscle will be considered in the neck. 



The SUPRASCAPULAR ARTERY is a branch of the subclavian, and Supra- 

 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 posterior belly of 

 the omohyoid muscle, to enter the supraspinous fossa. Its termi- 

 nation on the dorsum of the scapula will be seen in the dissection 

 of the shoulder (p. 38). Before entering the fossa it gives off a 

 ntpra-acromial brn.iich, which perforates the trapezius muscle, and offset, 

 ramifies over the acromion. 



The SUPRASCAPULAR NERVE is an offset of the brachial plexus Supra- 

 (fig. 8, p. 26), and inclines downwards beneath the omohyoid muscle SSS!" 

 to the notch in the upper border of the scapula, through which it 

 passes into the supraspinous fossa (p. 38). 



The TRANSVERSE CERVICAL ARTERY, also a branch of the Sub- Transverse 



clavian, has the same direction as the suprascapular, towards artery 1 



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



( 'rossing the upper part of the space in which the subclavian artery 



lies, it passes beneath the trapezius, and divides into two branches : divides into 



superficial cervical and posterior scapular. 



a. The superficial cervical branch is distributed chiefly to the superficial 

 under-surface of the trapezius, though it furnishes offsets to the levator e 

 anguli scapulae and the cervical glands. 



b. The posterior scapular branch crosses under the levator anguli posterior 

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

 rhomboid muscles. When these muscles are divided, the artery 



will be seen to furnish branches to them, and to give small anasto- 

 motic twigs to both surfaces of the scapula. This branch arises 

 very frequently from the third part of the subclavian trunk as a 

 separate artery from the superficial cervical. 



The suprascapular and transverse cervical veins have the same Accompany- 

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

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



