ELEMENTS OF MAMMALIAN ANATOMY. 



head, and anterior extremities with blood. The brachio- 

 cephalic gives off the left carotid and then divides into 

 the right carotid and right subclavian (Fig. 71). Some- 

 times the two carotids arise as a single trunk from the 



FIG. 71. VENTRAL ASPECT OF THE ARTERIES OF THE HEAD AND NECK 

 The carotids with their branches have been drawn laterad. 



a, Internal maxillary ; ac, anterior cerebellar ; cc, median cerebral ; cr, 

 posterior cerebral ; cp, posterior cerebellar ; ex, carotid plexus, many 

 of whose branches reunite into one, ex', which is cut off; ex, external 

 carotid; em, external maxillary; inc, origin of internal carotid; inc.', 

 union of internal carotid with circle of Willis; ia, inferior alveolar; 

 if, infraorbital; i, optic chiasma; li, lingual; mn, middle meningeal; 

 ms, muscular; oc, occipital; ol, anterior cerebral; pi, palatine; pa, 

 posterior auricular; s, anterior spinal; th, thyroid; x, hypophysis; 

 1, 2, 3, 4, 5, and 6, canal in cervical vertebrae. 



