THE COMMON CAROTID ARTEUY 



543 



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The left common carotid artery differs from the right one in that it is related 

 fleeply to the (esophagus, which separates 

 it from the tracliea in the greater part of 

 its cours(>. 



The colhiteral branches of the conmion 

 carotids are in tlie main sniaU. They com- 

 prise: 



1. Muscular branches (Rami muscu- 

 laresj of variable size, which go to the 

 ventral muscles of tlie neck and the skin. 



2. CEsophageal and tracheal branches 

 (Rami u-sophagei et ti'acheales). Small 

 twigs go to the cervical lymph glands also. 



3. Th(^ parotid artery. This comes off 

 near the termination and enters the ventral 

 part of the ixvrotid gland. It also supplies 

 thesubparotid lymph glands, and sometimes 

 sends a branch to the submaxillary gland. 

 It is inconstant. •' 



4. The thyro-laryngeal artery (A. thy- 

 reoidea cranialis). This, the largest col- 

 lateral branch of the carotid, arises from 

 the latter two or three inches before it j 

 divides. It curves over the anterior end \ 

 of the thyroid gland, into which it sends 

 sc\'eral bi-anches. It gives oft" a laryngeal 

 branch (A. laryngea), wdiicli sends t\\igs to 

 the external muscles of the larynx and the 

 constrictors of the pharynx, passes Ijetween 

 the cricoid and thyroid cartilages, and sup- 

 plies the internal muscles and the nuicous 

 meml)ranc of the larynx. A small pharyn- 

 geal branch (A. pharyngea ascendens) runs 

 upward and forward to the crico-pharyn- 

 geus, and supplies twigs to the ])osterior 

 part of the pharynx and the origin of the 

 esophagus. Small innominate twigs are 

 given off to the trachea, the oesophagus, 

 and the sterno-thyro-hyoideus and omo- 

 hvoidcus muscles. 





.some cases the thyroid and hiiyngeal 

 ari.se from the carotid separately or by 

 common stem. A hiryngeal branch is 



In 



arteries 



a short common stem. A 



often detached from the carotid in front of the 



thyro-laryngeal and enters the larynx with the 



superior laryngeal nerve. The pharyngeal Ijranch 



frequently comes directly from the carotid. 



Fig. 432. — Cross-section of Neck of Hoksk, 



P.\SS1.NG THROUGH FiFTH CeRVIC.\L \i R- 



tebra; Anterior View. 



a, Branches of cervical nerves; a', nuchal 

 fat; h, intertransversalis muscle; c, longi.ssimus 

 muscle; d, vertebral aiiery; e, vertebral vein; /, 

 vertebral nerve; y, spinal accessory nerve (upper 

 division); /;, recurrent nerve; i, vago-.sympa- 

 thetic trunk; A, tracheal lymjjh duct; /, body of 

 fifth cervical vertebra; /', transverse process of 

 same; m, carotid artery; n, jugular vein; o, 

 superior cervical artery; </. satellite vein of o; 

 p, sjiinal cord; q, dura mater; r, spinal vein; s, 

 ligamentum nuchae; t, rhomboideus muscle; 

 !/, splenitis; v, complexus; w, multifidus; x, 

 serratus cervicis; y, mastoido-humeralis; z, 

 sterno-cephalicus; 1, rectus capitis ant. major; 

 2, otno-hyoideus; S, panniculus; 4, sterno- 

 thyro-hyoideus; 6, longus colli; 6, 7, trachelo- 

 mastoideus; 8, trapezius; 9, spinalis; 10, 

 oesophagus; //, trachea, with cartilaginous 

 ring (II'), mucous membrane (11"), and mus- 

 cular layer (11'"). (After Ellenberger, in Lei.ser- 

 ing's Atlas.) 



5. The accessory thyroid artery (A. 

 thyreoidea caudalis) is an inconstant vessel 

 W'hich arises from the carotid at a vari- 

 al:)le distance behind the thyro-laryngeal — 

 sometimes from the latter or from the paro- 

 tid artery. It sends branches into the posterior part of the thyroid gland and 

 detaches small tracheal and muscular twdgs. In some cases it is distributed 

 chiefly or entirely to the adjacent nmscles. 



