SUPRA-SCAPULAR. TRANSVERSE CERVICAL. 373 



downwards with the suprascapular nerve towards the suprascapular notch. 

 At this point the nerve usually passes beneath the ligament stretched across 

 the notch, while the artery more frequently turns over it to enter the supra- 

 spinous fossa, where, lying close to the bone, it gives off branches which 

 ramify in the fossa beneath the supraspinatus muscle, and sends a small 

 communicating branch into the subscapular fossa, and is itself continued 

 down iuto the infraspinous fossa. 



BRANCHES. Muscular branches are given by the suprascapular artery to the 

 sterno-mastoid and other neighbouring muscles. 



(b) The supra-acromial branch passes obliquely forwards through the attachment 

 of the trapezius to reach the cutaneous surface of the acromion, on which it ramifies, 

 anastomosing with offsets from the acromial thoracic artery. 



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

 anastomoses with the posterior scapular and subscapular arteries in the subscapular 

 fossa and substance of the subscapularis muscle.. 



(d) 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. 



(e) Branches enter the bone and shoulder joint. 



PECULIARITIES. 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 subscapular branch 

 of that vessel. 



3. 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 

 aud 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 scapulae, 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 auguli scapulae, 

 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 scapulas, and then changing 

 its direction, runs downwards beneath the rhomboid ei muscles, as far as the 

 inferior angle of that bone. It anastomoses 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, communicating at the same time with the posterior muscular 

 branches of some of the intercostal arteries. 



PECULIARITIES. Not only does the transverse cervical branch of the thyroid axis 

 present the variation of being nearly as often the superficial cervical alone as of com- 

 prising also the posterior scapular artery, but it occasionally happens that the vessel 

 derived from the thyroid axis is very small, and represents only in part the superficial 

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

 divides near the levator anguli scapulae into two branches, of which one ascends and 



