////: i;i;.'iiiM. on .\\ii.i. M;Y i//v /:/,//>. hCl 



times hmg and voluminous, and partly supplements the superior cervical, 

 as is exemplified in the specimen which served for Fig. 282. 



Before leaving the thorax, the dorsal artery gives off some unimportant 

 lanuiscules and the gnli-nxtul (///</// i *HJH ;//-/ //(///.//// of Man). This 

 branch (Fig. 282, 5) curves backwards and. with the sympathetic chain, places 

 itself beneath the costo-vertchral articulations, against the long muscle of 

 the neck, furnishing the second, third and fourth intercostal arteries and 

 the corresponding spinal branches, and terminating at the fifth intercostal 

 space by either forming the artery which descends into that space, in 

 anastomosing by inosculation with a branch emanating from the first 

 rior intercostal artery, or by expending itself in the spinal muscles. 

 Frequently the second intercostal and its spinal branch come directly from 

 tlie dorsal artery ; the fifth also often arises from the posterior aorta. 1 



On the right side, tho dorsal artery always proceeds from a trunk common 

 to it and the superior cervical artery : a circumstance sometimes observed in 

 the left. This trunk has no relation with tho oesophagus. 



2. Superior Cervical, CbftftttMMMmiiar, <>r Deep Cervical Artery. 

 (Fig. 282, 6.) 



This vessel arises in front of the preceding artery, affects the same 

 relations in the thoracic cavity, which it leaves by passing between 

 the two first ribs, behind the last costo-transverse articulation ;' 2 it is 

 then directed upwards and forwards, passing beneath the inferior branch of 

 the ilio-spinal and great complexus muscles, courses in a flexuous manner 

 through the space comprised between the latter muscle on one side, and 

 the superior branch of the ilio-spinalis and cervical ligament on the 

 other, and arrives at the second vertebra of the neck, where its terminal 

 divisions anastomose with the branches of the occipito-muscular, vertebral, 

 and even the dorsal, arteries. 



The superior cervical artery distributes in its course : 1, The first inter- 



costal artery and the first spinal branch ; 2, Very numerous branches which 



\pended in the muscles and integuments of the cervical region, as well 



as in tin large ligament occupying the middle plane of that region ; among 



these branches, one longer than the others traverses the great complexus 



le to place itself between it and the splonius, and which is sometimes 



supplemented in great part by tho dorsal artery. 



3. Vertebral Artery. (Pig. 282, 7.) 



Arising at an acute angle from tho axillary artery at the first ii<; 



space, and covered at its origin by tho niediastiual layer, the vertebral 



artery proceeds forward and upward, within tho first rib, outside tho 



ihagos, 3 the trachea, and the inierior cervical ganglion, and is situated 



at the bottom of tho interstice separating the two portions of the seah-nus, 



with the fasciculus of branches originating from the hmchial plexus, which 



is a little above tho vessel. It then passes l.emath the. transverse process 



of tho seventh cervical vertebra, nnd traverses tin- series of cervical 



.inn, hidden beneath tin; intrrtransvorso muscles, to anastomose in 



t tin- ilcwMipli-'ii of tlif-so arti-iirs. s. e i a.^i- ?>-!. 

 \\V have seen it escape, along with the dorsal artt-ry, \>y tin- MV..H.I int. ,. 



3 hi tin- li^'lit, those rolntioiiH with the n'siijilin^iiH an> not pr- 



