BRANCHES OF THE SUBCLAVIAN ARTERY. 585 



Surgical Anatomy. This artery is sometimes tied, in conjunction with the superior thy- 

 roid, in cases of bronchocele. An incision is made along the anterior border of the Sterno-mas- 

 toid down to the clavicle. After the deep fascia has been divided, the Sterno-mastoid and caro- 

 tid vessels are drawn outward and the carotid (Chassaignac's) tubercle sought for. The vessel 

 will be found just below this tubercle, between the carotid sheath on the outer side of the trachea 

 and oesophagus on the inner side. In passing the ligature great care must be exercised to avoid 

 including the recurrent laryngeal nerve. 



The Suprascapular Artery (transversalis humeri), smaller than the transversalis 

 colli. passes obliquely from within outward, across the root of the neck. It at 

 first lies on the lower part of the Scalenus anticus, being covered by the Sterno- 

 mastoid : it then crosses the subclavian artery, and runs outward behind and par- 

 allel with the clavicle and Subclavius muscle, and beneath the posterior belly of 

 the Omo-hyoid, to the superior border of the scapula, where it passes over the 

 transverse ligament of the scapula to the supraspinous fossa. In this situation it 

 lies close to the bone, and ramifies between it and the Supraspinatus muscle, to 

 which it is mainly distributed, giving off a communicating branch which crosses 



Posterior scapular. 



tiiprascapular. Acromiat branch 



Of Thoracico-acromialis. 



Anterior 

 circumflex. 



I 



-Termination of 

 subscapular. 



FIG. 36L The scapular and circumflex arteries. 



the neck of the scapula, to reach the infraspinous fossa, where it anastomoses with 

 the dorsal branch of the subscapular artery. Besides distributing branches to the 

 Sterno-mastoid and neighboring muscles, it gives off a supra-acromial branch, 

 which, piercing the Trapezius muscle, supplies the cutaneous surface of the acro- 

 mion. anastomosing with the acromial thoracic artery. As the artery passes over 

 the transverse ligament of the scapula a branch descends into the subscapular 

 fossa, ramifies beneath that muscle, and anastomoses with the posterior and sub- 

 scapular arteries. It also supplies the shoulder-joint and a nutrient branch to the 

 clavicle. 



The Transversalis Colli passes transversely outward, across the upper part of 

 the subclavian triangle, to the anterior margin of the Trapezius muscle, beneath 

 which it divides into two branches, the superficial cervical and the posterior scap- 

 ular. In its passage across the neck it crosses in front of the Scaleni muscles and 

 the brachial plexus, between the divisions of which it sometimes passes, and is 

 covered by the Platysma, Sterno-mastoid, Omo-hyoid, and Trapezius muscles. 



The superficial cervical ascends beneath the anterior margin of the Trapezius, 

 distributing branches to it and to the neighboring muscles and glands in the neck, 

 and anastomoses with the supei'ficial branch of the arteria princeps cervicis. 



The posterior scapular, the continuation of the transversalis colli, passes 



