THE TRANSVERSE CERVICAL ARTERY. 389 



communicating branch into the subscapular fossa, and is itself con- 

 tinued down into the infraspinous fossa. 



Branches. — Muscular branches are given by the suprascapular artery to the 

 stemo-mastoid and other neighbouring muscles. 



(&) The siqjra-acromial branch passes obliquely forwards through the attach- 

 ment of the trapezius to reach the cutaneous surface of the acromion, on which 

 it ramifies, anastomosing with offsets from the acromio- thoracic artery. 



(c) A smaU subscapular branch, given off as the artery passes over the notch, 

 anastomoses "with the posterior scapular and subscapular arteries in the sub- 

 scapular fossa and substance of the subscapularis muscle. 



((/) An infraspinous branch is continued from the suprascapular artery, and 

 descending close upon the neck of the scapula, between the glenoid cavity and 

 the spine of that bone, joins with the dorsal branch of the subscapular artery, 



(<") Branches enter the bone and shoulder johit. 



Varieties. — The suprascapular artery has in some cases been observed to spring 

 directly from the subclavian, or to arise from that vessel by a common trunk 

 with the transverse cervical, or more rarely with the internal mammary. 

 It has also been found to proceed from the axillary artery, and from the sub- 

 scapular branch of that vessel. 



C. The transverse cervical artery, the third branch of the thyroid 

 axis, passes outwards a short distance above the clavicle, and therefore 

 higher than the suprascapular artery. It crosses over the scaleni 

 muscles and the brachial plexus, sometimes passing between the nerves 

 of the latter, and is crossed by the omo-hyoid muscle. Beneath the 

 anterior margin of the trapezius, and near the outer edge of the levator 

 anguli scapulffi, it divides into two branches, the superficial cervical and 

 the posterior scapular. 



The superficial cervical artery ascends beneath the anterior border of 

 the trapezius, and distributes branches to that muscle, the levator 

 anguli scapulifi, and sterno-mastoid muscles, as well as to the cervical 

 glands and the integuments in the intervals between those muscles. 

 When the posterior scapular arises separately from the subclavian, the 

 name superficial cervical may be given to the whole remaining part of 

 the transverse cervical artery. 



The posterior scapular artery, whether arising from the transverse 

 cervical artery or directly from the subclavian, passes backwards to the 

 upper angle of the scapula, under cover of the levator anguli scapulte, 

 and then changing its direction, runs downwards beneath the rhom 

 boidei muscles, as far as the inferior angle of that bone. It anasto- 

 moses freely on both surfaces of the scapula with the divisions of the 

 suprascapular and subscapular arteries ; and supplies branches to the 

 rhomboidei, serratus magnus, and latissimus dorsi muscles, communi- 

 cating at the same time with the posterior muscular branches of some 

 of the intercostal arteries. 



Varieties. — Not only does the transverse cervical branch of the thyi'oid axis 

 present the variation of being nearly as often the superficial cei-vical alone as of 

 comprising also the posterior scapular artery, but it occasionally happens that the 

 vessel derived from the thyroid axis is very smaU, and represents only ia part the 

 superficial cervical artery ; whilst a large vessel arising from the third part of 

 the subclavian divides near the levator anguli scapulas iato two branches, of 

 which one ascends and represents the remaining and larger portion of the super- 

 ficial cei-vical artery, while the other forms the posterior scapular. 



The transverse cervical artery is sometimes derived directly from the subclavian, 

 beneath or even beyond the scalenus anticus muscle. The transverse cervical 

 sometimes gives off the ascending cervical artery. 



