THE HEAD AND NECK 1143 



The transverse cervical artery passes transversely outwards in 

 front of the scalenus anticus and phrenic nerve, and behind the 

 clavicular part of the stemo-cleido-mastoid, lying a little above 

 the clavicle, and also above the suprascapular artery. It then 

 enters the subclavian triangle, which it soon leaves by passing 

 beneath the posterior belly of the omo-hyoid. Thereafter it passes 

 in front of, or between, the nerve-trunks of the brachial plexus, 

 and beneath the trapezius muscle. Having reached the anterior 

 border of the levator anguli scapulae, it divides into its two terminal 

 branches — superficial cervical and posterior scapular. 



The superficial cervical artery passes superficial to the levator 

 anguli scapulae, and is distributed to the trapezius, levator anguli 

 scapulae, splenius, and the adjacent lymphatic glands. The pos- 

 terior scapular artery passes backwards beneath the levator anguli 

 scapulae to the superior angle of the scapula. Thereafter it descends 

 along the base of the bone, imder cover of the rhomboid muscles, 

 as far as the lower angle, where it anastomoses with the teres branch 

 of the dorsalis scapulae of the subscapular from the third part of the 

 axillary artery. The artery gives branches to the adjacent muscles, 

 and ventral and dorsal branches to the scapula, which take part in 

 the scapular anastomoses proper (see p. 325). 



The posterior scapular artery is frequently a branch of the third 

 part of the subclavian, in which cases there is no transverse cervical 

 artery, the superficial cervical artery taking its place and arising 

 from the thyroid axis. 



The suprascapular artery (transversalis humeri) passes downwards 

 and outwards in front of the scalenus anticus and phrenic nerve, 

 and behind the clavicular part of the stemo-cleido-mastoid. Having 

 reached the back of the clavicle, it courses outwards behind that 

 bone, passing in front of the third part of the subclavian artery and 

 the trunks of the brachial plexus. It then passes to the upper 

 border of the scapula, in company with the suprascapular nerve. 

 For the further course of the vessel see p. 320 ; and for the scapular 

 anastomoses of arteries see Index. 



Branches in the Neck. — ^These are as follows : muscular, supra- 

 sternal, and medullary. The muscular branches supply the stemo- 

 cleido-mastoid and subclavius. The suprasternal branch descends 

 over the inner end of the clavicle to supply the integument over the 

 manubrium stemi. The medullary artery of the clavicle is directed 

 outwards, and enters the medullary foramen of that bone. 



Superior Intercostal Artery. — ^This vessel arises from the second 

 part of the subclavian on the right side, and from the first part on 

 the left side, in each case from the posterior aspect of the parent 

 trunk. On the right side it is therefore behind the scalenus anticus, 

 and on the left side close to the inner border of that muscle The 

 vessel at first passes backwards for a short distance, and then 

 descends in front of the neck of the first rib. At the posterior 

 extremity of the first intercostal space it furnishes the first inter- 

 costal artery to that space, and then descends in front of the neck 



