l6o ELEMENTS OF MAMMALIAN ANATOMY 



internal carotid and gives off several arteries to the cerebrum. 

 In man the internal carotid is much larger proportionately 

 than in the cat (Fig. 74). The branches of the basilar artery- 

 are the posterior inferior eerebellar, anterior cerebellar and pos- 

 terior cerebral arteries. 



THE ARTERIES OF THE THORACIC LIMB 



There is more or less variation in the branching of the arteries 

 in the limbs. No two cats are found exactly alike as to their 

 arteries or veins. The same is true of all other mammals. 



The subclavian artery, which on the right side springs from, 

 or is merely a continuation of, the innominate and on the left 

 side arises from the arch of the aorta, supplies the forelimbs 

 with blood (Figs. 79 and 80). When the subclavian reaches the 

 armpit, it is called the axillary artery, and its continuation 

 along the humerus is the brachial artery. A continuation of the 

 same artery along the radius is the radial artery, furnishing a 

 large part of the blood to the fingers. 



Four branches arise from the subclavian: (i) the vertebral 

 artery, extending to the brain through the transverse foramina 

 of the cervical vertebrae (2) the internal mammary, arising 

 from the ventral side of the subclavian opposite the origin of 

 the vertebral, and extending along the visceral surface of the 

 sternum and sometimes supplying the pericardium of the 

 heart; (3) the costocervical axis, arising near the vertebral 

 artery, it gives off the superior intercostal artery supplying the 

 first and second intercostal spaces and some deep muscles of 

 the neck, and the transversa colli to the serratus anterior and 

 continues as the deep cervical (cervicales profunda) to supply 

 the deep muscles of the neck; and (4) the thyreoid axis, extend- 

 ing craniad giving off the ascending cervical to some muscles of 

 the neck, and the transverse scapular to the lateral aspect of 

 the scapula (Fig. 80). 



The axillary artery gives origin to three branches: (i) the 

 anterior thoracic, supplying the pectoral muscles; (2) the long 

 thoracic, distributed chiefly to the latissimus dorsi; and (3) the 



