572 THE ARTERIES. 



with its liomologue; it is directed buck ward and downward on the hull) of (lit- ]>}. 

 where it forms an ana.*t< 'motic arch with tin- lateral digital artery ; from tin- con 

 of this arch, which is turned downwards, there escape a larjie nnml.iT of reticulating 

 ramuacules, destined for the keratogcnous membrane and the plantar cushion. 



c. The lateral diyilal nrt< rit-x are distinguished into inti runl ;md / .>/- ninl. The lir-1 

 has its origin at the bend formed by the collateral of tin- cannon, when t< 

 inflected on the posterior face of the perforatus tendon to IMC,, me the median d 

 artery, most frequently in common with the branch whose divir-ions join the UK I, 

 interoaseous arteries. The second commences a little further oft', ufter having invivrd a 

 branch from either this communicating artery, or from the external inti -n . mi.- palmar ; 

 it is not rare to see it entirely formed by one of these branches, or l>y the two togi-thcr. 

 Whatever may lie their point of origin, the lateral digital arteries descend on the ex- 

 centric side of the digits, without the flexor tendons, and terminate in anastomosing 

 by inosculation with the artery of the plantar cushion. Among the collateral bra 

 emanating from these arteries, there ought to be distinguished thnt which goes to the 

 ergot, and the transverse branch thrown across between each, as well as the nidiim 

 digital artery. 1 



2. Axillary Arteries of the Pig. 



Both spring separately from the arch of the aorta; consequently, there is no antei ior 

 aorta. The right artery, or Irachio-cephalic trunk, first arises ; the left comes immediately 

 after. 



a. The bra/-hio-cephalic trunk is directed forwards, under the inferior face of the trachea, 

 and leaves the thorax to reach the inner face of the anterior limb, as in other animal-. 



It furnishes successively : 



1. At the first rib, and below, the two carotid arterier, rising singly from nearly the 

 same point. 



2. Directly opposite to these vessels, a trunk remarkable for the complication 

 attending its mode of distribution ; it is directed upwards and backwards, on tin- -idr 

 of the tracln a and longus colli, crosses the interval between the second and third rihs, 

 and elevates itself into the deep cervical muscles, to terminate in the vicinity of the nape 

 of the neck. It evidently represents the deep or superior ctrrirtil <n-t< ///. Near its origin 

 it gives oft* the vertebral artery, whose mode of termination is exactly the same a> in tin: 

 Horse. Beyond this, it detaches the dorsal artery, which ascends into the muse].- of 

 the withers, after passing into the first intercostal space. Lastly, it supplies, h, ton 

 leaving the thorax, the subcoxtal or superior intercostal artery, placed across the superior 

 extremities of the third, fourth, and fifth ribs. 



3. Always within, but a little more forward than the first rib, a voluminous in/- 

 cervical artery, divided into several ascending branches; and the twotlnn-in-;,- </, 

 which offer nothing particular for description. 



4. Without the thorax, on the internal face of the scapulo-humeral articulation, the 

 humeral or subfcapular arteries; the first, less voluminous than the other, presents, from 

 its origin to the distribution of its branches in the foot, a disposition essentially 

 resembling that observed in this vessel in Knminants; the second courses upward- in 

 the space between the subscapular muscle and the teres mnjor, nnd soon divides into 

 two terminal branches, one of which continues the primitive track of tho vessel, while 

 the other passes beneath the subscapular muscle to carry its ramifications into tho 

 antero-extci-nal muscles of the shoulder, furnishing in its course : 1, Th ;rn at dor.-al 

 artery, throwing a part of its ramifications into the olecranian muscles: 2, A volu- 

 minous branch which provides the greater number of the divisions given off, in the 

 Horse, by the deep humeral and prehumeral arteries; 3, Two articular branches, one 

 of which closely represents the superscapular artery. 



6. The left brachiol trunk only (lifters from the right in the disposition of the 

 superior cervical, dorsal, and vertebral aiteries, which have distinct origins; the two 

 last are very close to each other, and the first furnishes the subcostal branch. 



3. Axillary Arteries of Carnivora. 



These arise separately from the convexity of the arch of tho aorta, as in the Pig, nnd 

 furnish successively, apart from the carotids, special branches of the brachio-cephalic 

 trunk : 



1. A voluminous trunk, the common origin of the dorsal, superior cervical, and nil- 



1 In several instances, we have wen the lateral digital arteries stop at this transverse 

 anastomosis, which then received them entirely. 



