258 LABORATORY MANUAL FOR VERTEBRATE ANATOMY 



chest wall and continues on the abdomen as the superior epigastric artery. A 

 the same level from the posterior surface of the subclavian, practically in commc 

 with the preceding, the supreme intercostal artery arises. It runs posteriorly c 

 the dorsal wall of the thorax and receives the first intercostal arteries. On i 

 anterior surface at about the same level as these the subclavian artery gives ris 

 to the vertebral artery which passes immediately dorsad toward the cervical ve: 

 tebrae where it enters the vertebrarterial canal; and to the superficial cervia 

 artery which ascends in the lateral part of the neck, supplying various muscle 

 its main branch {ascending cervical) accompanying the external jugular veil 

 The transverse artery of the neck leaves the subclavian at the same place or i 

 common with the supreme intercostal artery. It passes dorsally in front of th 

 first rib through a loop formed by two nerves, and emerges on the medial sid 

 of the serratus ventralis muscle. It is best found by looking on this muscle an 

 then tracing the artery toward the subclavian. After giving off the foregoin 

 branches the subclavian passes in front of the first rib into the axilla where i 

 is named the axillary artery. This lies between two of the stout nerves belong 

 ing to the brachial plexus. Its branches are similar to those of the axillary vei 

 and accompany the veins. After giving rise to the small thoracoacromial arter 

 to the pectoral and deltoid muscles, the axillary gives off the long thoracic an 

 subscapular arteries, accompanying the veins previously described. The forme 

 runs posteriorly along the serratus muscle and then as the external mammar 

 artery passes to the under surface of the skin of the lateral abdominal wall, bein 

 especially conspicuous in females. (Most of this vessel was destroyed in remov 

 ing the skin.) The subscapular has a conspicuous branch {thoracodorsal artery 

 passing caudad to the latissimus dorsi and cutaneous, maximus muscles; i 

 then turns dorsally and perforating the teres major emerges on the outer surfac 

 of the shoulder, supplying various muscles. Near the point of origin of th 

 subscapular the deep artery of the arm arises, and after giving off branches int 

 the subscapular muscle passes between this muscle and the teres major to th 

 dorsal part of the arm where it runs in company with one branch of the cephali 

 vein and a nerve, all three situated internal to the lateral head of the triceps whic 

 should be deflected. The axillary artery now passes to the upper arm, where a 

 the brachial artery it courses along the inner surface of the limb in compan 

 with the brachial vein and nerves. 



Draw the branches of the subclavian. 



Cat: The subclavian first gives rise to the costoccrvical axis. This divide; 

 One branch, the supreme intercostal artery, passes posteriori}-, giving off intet 

 costal branches, and then runs along the mid-dorsal line of the thorax, supplyin 

 the deep muscles of the back. The other branch of the costocervical axis leave 

 the thoracic cavity, passing deep dorsally in front of the first rib, and gives ris 

 to the transverse artery of the neck, supplying the serratus ventralis and rhombo: 

 deus muscles, and the deep cervical artery to the epaxial muscles of the necl 



