638 



BLOOD-VASCULAR SYSTEM OF THE HORSE 



In some cases the thyroid and laryngeal arteries arise from the carotid separately or by a 

 short common stem. A laryngeal branch is often detached from the carotid in front of the thyro- 

 laryngeal and enters the larjTix with the anterior laryngeal nerve. The pharyngeal branch fre- 

 quently comes directly from the carotid. 



Fig. 558. — Deep Dissection of Neck of Hohse. 

 a, a, Ends of sterno-cephalicus; 6, anterior part of omo-hyoideus ; c, sterno-thyro-hyoideus; d, trachea; e, oesopha- 

 gus; /, cariniforEa cartilage; g, rectus cap. ventrahs major; h, stump of longissimus atlantis; i, intertransversales; fc, 

 multifidus; I, m, scalenus; n, serratus cervicis; o, o, stumps of splenius; p, longissimus cervicis; q, complexus (most of 

 ■which is removed) ; r, rhomboideus; s, trapezius; t, spinalis et semispinahs ; u, lamellar part of lig. nuchte; v, brachio- 

 cephahcus; w, anterior deep pectoral; x, supraspinatus; y, anterior superficial pectoral; z, tuber scapulae; i , i , articular 

 processes of cervical vertebrEc; 2, 2, transverse processes of same; 3, atlas; 5', axis; 4- A, jugular vein (remainder re- 

 moved) ; 5, common carotid artery, from which a piece is removed to show the accompanying nerves and the oesophagus; 

 6, vago-sympathetic trunk; 7, 7, tracheal and muscular branches of carotid artery; 8, recurrent nerve; 10, left tracheal 

 lymph-duct; 11, 12, ascending and descending branches of inferior cer\'ical artery {13) ; 14, cephalic vein; 15-20, ven- 

 tral branches of second to seventh cervical nerves; 21, roots of phrenic nerve; 22, pectoral nerves; 22', nerve to ser- 

 ratus ventralis ; ^3, musculo-cutaneous nerve; ^4, median nerve; ^5, ulnar nerve; ^ff, radial nerve; ^7, axillary nerve; 

 2S, dorsal branches of cervical nerves; 28', accessory nerve (cut) ; 29, deep cervical artery; 30, muscular branch of ver- 

 tebral artery; 31, posterior branch of occipital artery; 32, vertebral artery; 33, muscular branches of occipital artery; 

 SA, obhquus capitis post.; 35, obi. cap. ant.; 36, twig from dorsal branch of third cervical nerve, (After Ellenberger- 

 Baum, Top. Anat. des Pferdea.) 



^: The posterior thyroid artery (A. thyreoidea caudalis) is a small and incon- 

 stant' vessel which arises from the carotid at a variable distance behind the anterior 

 thyroid or from the latter or the parotid artery. It sends branches into the pos- 

 terior part of the thyroid gland, and detaches small tracheal and muscular twigs. 

 In some cases it is distributed chiefly or entirely to the adjacent muscles. 



