SHOULDER SCAPULAR REGION 91 



Arteria Circumflexa Scapulae (O.T. Dorsalis Scapulae 



Artery). The circumflex scapular artery, as already noted, 

 arises from the subscapular branch of the axillary and enters 

 the triangular space. While there it supplies one or two 

 ventral branches, which pass, under cover of the subscapular 

 muscle, to the subscapular fossa, and a larger infrascapular 

 branch, which runs downwards, in the interval between the teres 

 major and teres minor, to the inferior angle of the scapula 

 (Figs. 34, 35, pp. 79, 80). After those branches are given 

 off, the circumflex scapular artery leaves the triangular space 

 by turning round the axillary border of the scapula, under 

 cover of the teres minor. It now enters the infraspinous 

 fossa, where it ramifies, and supplies branches to the infra- 

 spinatus muscle. 



Arteria Thoracodorsalis. The thoraco-dorsal branch of 

 the subscapular artery runs along the axillary border of the 

 scapula on the lower margin of the subscapularis. It sends 

 branches into the subscapular fossa which supply the sub- 

 scapularis and anastomose with branches of the descending 

 branch of the transverse cervical artery, and the transverse 

 scapular and circumflex scapulte arteries. 



When the dissector has followed the branches of the four 

 arteries just considered, he will realise that the arterial 

 anastomosis around the scapula is very complete. In the 

 supraspinous fossa branches of the descending branch of the 

 transverse cervical artery and the transverse scapular artery 

 anastomose. In the infraspinous fossa branches of the 

 descending branch of the transverse cervical, the transverse 

 scapular, and the subscapular artery anastomose, and branches 

 of the same three arteries anastomose in the subscapular 

 fossa. The importance of these free communications is 

 manifest when it is remembered that two of the main arteries, 

 viz., the descending branch of the transverse cervical artery 

 and the transverse artery of the scapula, spring indirectly from 

 the first part of the subclavian ; whilst the third, viz., the 

 subscapular, arises from the third part of the axillary. When, 

 therefore, a ligature is applied to any part of the great arterial 

 trunk of the upper limb, between the first stage of the sub- 

 clavian and the third part of the axillary, the anastomosis 

 round the scapula affords ample means of re-establishing the 

 circulation. 



Nervus Suprascapularis. The suprascapular nerve 



