138 ELEMENTS OF MAMMALIAN ANATOMY. 
posite the origin of the vertebral, and extending along the 
visceral surface of the sternum, and sometimes supplying 
the pericardium of the heart; the superior intercostal, aris- 
ing near the vertebral artery and supplying the first and 
second intercostal spaces, the deep muscles of the back, and 
the serratus magnus; and the thyroid axis, extending 
craniad to supply some muscles of the neck and the lateral 
aspect of the scapula (Fig. 74). 
The avillary artery gives origin to three branches: the 
anterior thoracic, the long thoracic, and the circumflex. 
The anterior thoracic supplies the pectoral muscles. The 
long thoracic is distributed chiefly 
to the latissimus dorsi. The cir- 
cumficy artery is almost as large 
as the continuation of the axillary, 
which beyond this point is called 
the brachial. The circumflex, 
about a centimeter from its ori- 
gin, after giving off the subscapu- 
lar, which is distributed mainly to 
Fic. 74. ARTERIES OF THE FOoRELIMB. 
VENTRAL ASPECT. 
a, Digital artery; an, anastomotica 
magna; ac, anterior circumflex; ai, 
anterior interosseous; ar, axillary; at, 
anterior thoracic; b, digital artery; be, 
innominate; br, brachial; c, dorsal 
branch of the radial where it passes 
between the second and third meta- 
carpals to the palmar side; ca, circum- 
flex; is, superior intercostal; /s, left 
subclavian; Jt, long thoracic; m, 
branch to extensor muscles; mt, nutri- 
ent; pt, posterior interosseous; 1, 
radial; rd, radial recurrent; sf, supra- 
condyloid foramen of the humerus; 
Spr, superior profunda; sb, subscapu- 
laris; sp, suprascapularis; st, sternal; 
th, thyroid axis; wl, ulnar; ur, ulnar 
recurrent; vt, vertebral. 
