160 



ANATOMY AND PHYSIOLOGY OP 



toe of the frog, where they end in commu- 

 nications with the arteries of that body. 



THE CAROTID ARTERY. 



The right arteria innominata, having de- 

 tached seven important branches, which 

 vary but little in their mode of origin, 

 general course, and distribution, from the 

 several arteries into which the left division 

 resolves itself, become the common carotid 

 — a large vessel emerging through the up- 

 per opening of the chest ; it divides, as it 

 quits the chest, into t\vo branches, called 

 the right and left carotids. These arteries 

 ascend, and having reached the top of the 

 lEirynx, the carotid of either side branches 

 into three divisions — the external and inter- 

 nal carotids, and the ramus anastomoticus : 

 here, though the trunk itself becomes deeply 

 lodged in soft parts, its situation is well in- 

 dicated by the larynx, with which it is in 

 contact. This vessel detaches — 1. Several 

 unimportant muscular branches in its pro- 

 gress up the neck. 2. The thyroideal 

 artery, which furnishes the laryngeal, a 

 small artery that perforates the ligament 

 uniting the cartilages of the throat. 



The external carotid artery is the large 

 division, which may be regarded as the con- 

 tinuation of the carotid itself. This artery 

 is imbedded in glandular substance, sur- 

 rounded by venous and nervous trunks, and 

 protected by bony prominences and muscles. 

 The first branch of the external carotid is 

 the submaxillary artery ; it comes off behind 

 the horn of the ox hyoides, just as the 

 carotid makes its second curve, and ranks 

 next in size to the trunk itself. After reach- 

 ing the lower jaw (about one-third of its 

 length downwards), it arrives upon the face; 

 here it becomes subcutaneous, ending in an 

 equal division, called the facial and inferior 

 labial arteries. Its branches are, the ascend- 

 ing laryngeal, pharyngeal : smaller branches 

 go to parotid gland, and a large branch, 

 called the lingual. The latter detaches a 

 few twigs into the submaxillary space ; it 

 then branches into two arteries, the ranine 

 and the subhngual. The ranine, apparently 

 a continuation of the lingual, passes along 



the under part of the tongue, and transmits 

 branches to the interior, and continues of 

 large size even to the tip of the orgp^n, 

 wherever its extreme ramifications are ex- 

 pended. The sublingual artery winds along 

 the under and outer border of the tongue, 

 preserving a more superficial course than 

 the former. It supplies the sublingual 

 gland, and distributes branches over the 

 membrane of the tongue. The submental 

 artery leaves the submaxillary, follows the 

 course of the branch of the jaw, and de- 

 taches twigs to muscles ; it then transmits 

 its ramifications into the gums internally. 

 The anterior masseter branches pass on the 

 external side of the jaw. 



The infet'ior labial artery courses the side 

 of the jaw, invested in the cellular and 

 fleshy substance belonging to the buccinator. 

 It gives off slender ramifications to the in- 

 vesting cellular substance, also the buc- 

 cinator arteries ; the buccal twigs bifurcate, 

 sending their divisions respectively to the 

 upper and under lips ; these form the supe- 

 rior and inferior coronary arteries of the lips. 



The facial artery ascends upon the side 

 of the face, crosses the buccinator, then, 

 having run as high as the bony ridge from 

 whence the masseter arises, it detaches a 

 large branch, and then expands upon the 

 upper and fore part of the face ; its termi- 

 nating ramifications are in the cellular sub- 

 stance and skin covering the fore part of 

 the face. 



The posterior auricular gives branches to 

 the parotid gland, and to the different mus- 

 cles of the ears. 



The temporal artery ^\h& anterior auricular, 

 and the internal maxillary, may be con- 

 sidered as the terminating branches of the 

 external carotid. The internal maxillary 

 gives off deep temporal branches, long 

 slender twigs, to the soft palate, to the ear, 

 and to the articulation of the jaw; the facial 

 artery also gives off the inferior maxillary, 

 the supra-orbitar, the ocular, the infra- 

 orbitar, and the palate maxillary. The 

 second and smallest division of the carotid 

 is the 



