90 THE SUPERIOR EXTREMITY 



Dissection. Revise the arteries which lie in relation with 

 the borders and surfaces of the scapula, and dissect out the 

 anastomosis between their branches. Descending along the 

 vertebral border is the descending branch of the transverse 

 cervical artery. Crossing the superior border is the supra- 

 scapular artery. The subscapular artery was seen during the 

 dissection of the axilla ; it springs from the third part of the 

 axillary, descends for about 25-30 mm. along the inferior border 

 of the subscapularis, and then divides into circumflex scapular 

 and thoraco -dorsal branches. The circumflex scapular at once 

 turns round the axillary border of the scapula and passes, deep 

 to the teres minor, to the infraspinous fossa. Follow the rami- 

 fications of both branches to their anastomoses with the adjacent 

 arteries. 



The Anastomosis around the Scapula. An important and 

 free anastomosis takes place between the branches of three 

 arteries which lie in close relation with the scapula, viz. : (i) 

 the descending branch of the transverse cervical artery ; (2) 

 the transverse scapular artery ; (3) the circumflex scapulae and 

 thoraco-dorsal branches of the subscapular artery. 



The Descending Branch of the Transverse Cervical 

 Artery was seen when the levator scapulae and the rhomboids 

 were reflected. It runs downwards along the vertebral border 

 of the scapula in the angle between the levator scapulae and 

 the rhomboids, which are behind it, and the insertion of the 

 serratus anterior, which is in front of it. It sends branches 

 into the subscapular fossa and into the supra- and infraspinous 

 fossae, which anastomose in all three regions with branches of 

 the transverse scapular and subscapular arteries, and at the 

 inferior angle of the scapula it anastomoses with the terminal 

 branches of the thoraco - dorsal branch of the subscapular 

 artery. 



Arteria Transversa Scapulae (O.T. Suprascapular Artery). 

 The transverse scapular artery enters the supraspinous 

 fossa by passing over the ligament which bridges across the 

 scapular notch. It divides, under cover of the supraspinatus 

 muscle, into a supraspinous and an infraspinous branch. The 

 former supplies the supraspinatus muscle, and gives off the 

 chief nutrient artery to the scapula ; the latter proceeds down- 

 wards through the great scapular notch, under cover of the 

 inferior transverse scapular ligament, to reach the deep surface 

 of the infraspinatus muscle, to which it is distributed. 



At the superior border of the scapula the transverse artery 

 of the scapula gives off a subscapular branch, which enters the 

 subscapular fossa, under cover of the subscapularis muscle. 



