THE HHArillAL in; AXILLARY ARTERIES 573 



' or tuperior iiittn-oxlttl arteries : tin- tir.-t pa-.-es between tin- two anterior ril>s ; tin- 



I in fiont uf tho first; the third across tin- internal fa -f the lir.-t. .second, nd 



third ribs in-ar their eartihges. win -iv it, emit.- a-cemling and descending intercostal 



shee. 



J. 'I'll. r/7< //rii/ <(//( nj, anastomosing, as in Solipeds, with a retrograde branch from 

 the o,-cipital artery; it supph m. nts. in s.iy great part, th'- superior cervical, whose 

 volume is diminutive, and which is only di.-tnhnted to tin- jHisti-rior \ art of the neck. 



3. The inferior c> n-i'-iil n/ii /</. giving nil' the pectoral blanches. 



4. The internal tl<r<i<-i-- nrlery, remarkable for its large volume, and for a superficial 

 division chiefly destined to the mamma', \\hich joins an antilogous branch from the 

 external pudic artery. 



.">. A -I stii-Hii! thoracic branch, whose origin more resembles tl.at of the supfr- 

 fu/.iil.u- artery, which appears to be absent. 



'!. The subsca put tir <nt< ry. After furnishing this vessel, the brachial trunk is pro- 

 '1 l>y the humeral artery, which we will now examine in detail. 



Hi MI:;:AL ARTEKY. Placed at first immediately behind the coraco-radiul or biceps 

 mu-cle, tin- YI ssel descends beneath the round pronator, and divides at the superior 

 extremity of the radius into two terminal branches; these are the ulnar and radial 

 a rt> , 



It detaches on its course collateral branches, analogous to those which have been 

 described for Solipeds, and among which is a thin vessel, a vestige of the anterior radial 

 artery, that passes beneath the terminal extremity of the biceps to supply the muscles 

 covering, anteriorly, the articulation of the elbow. 



/'/ .Much smaller than the radial, this vessel transmits, near its origin, 



the intrruwout art- nj. which sometimes proceeds directly from the humeral artery, and 

 w In >.-e calibre always exceeds, in animals, that of the ulnar artery. The latter is directed 

 obliquely outwards and downwards, passing under the perforans, and gains the internal 

 'f the anterior ulnur or oblique flexor of the metacarpus, where it lies beside the 

 ulnar nerve, to descend with it inside the unciform bone, and join the posterior interosseous 

 artery, or one of its terminal branches. On its track it gives off a number of muscular 

 or cutaneous brandies, several of which anastomose with the internal collateral artery 

 of the elbow, as well as witli divisions of the radial artery. 



luteroeseous artery. This artery is placed between the cubitus and radiu?, under- 

 ntath the square pronator, and is prolonged to the lower third of the fore-arm, where it 

 separates into two branches the anterior and posterior interosneous arteries, after 

 abandoning on its way several branches, mostly anterior, which enter the antibrachial 

 muscles by traversing the space comprised between the two bones of the fore-arm, the 

 prini-ipal escaping by the radio-ulnar arch. 



The anti-i-i'if iiit' rowou* artery, after passing between the radius and ulna, de.-.-i n.!s 

 on the anterior face of the carpus, where its divisions met t. inwardly, the collateral 

 ranmscules of tlic radio-palmar nrtery, and outwardly, the urlxirisations of a branch from 

 the posterior interossious artery, forming with i Is a wi'le-meshcd |il.-.\us, 



from which definitively proceed several filaments that join the dorsal intfrosseous 

 in. taearpal art. 



'J'he //<>/. ,-ior inttroueout artery may be regarded, by its volume and din dion, as the 



continuation of the in; link. After en,< r-'nu' from 1 t neath the square pmnator. 



it il- 1 it-lies an internal hYxuous branch anastomosing with the radio-palmar art. ry, then 



il external mii.-ciiliMMiiane.uis branches; alter which it i.s placed within the 



pi.-iform IMUIC, where it divides into two liranche.-, after receiving the ulnar artery. The 



Mnali branches anastomoses by ino.-cula'ion with the sn|x-rlieial palmar arch ; 



the .,tli. r. 1 1 ]_-, T ami tie. |M-r-.-eatl, is carried in front of the flexor tendons, U-ncath the 



ur-.-is covering the iuterosseous muscles, acr.'.-.- the >ii]H-rior extremity of ih. .-., a-nl 



so forming the <!> i> /nilin'ir fii-i-l,. which unites \\itii a thin filament from the ladio-palinar 



. . This arcli stipjili. s. with .-ome lamu.-cules destiiiitl to the muscles of the haml 



(or paw), /.//</ interotteotu mefacar/Kil rt< //> .- / "r iilmnr, wliich are nn.t. .1 



by tlieir inferior exrremity w ith the ctdl.tteial- of tin- .1 L-I' -. after giv ing several divisions 



to tho nniM-1. - .,f the h:in<l ; ami /our anttrinr or dorttil. tiav- -ibimr the Mipeiior extremity 



of tin- int. rmetacarpal .-pace.-, like tli. ; <irt,ri.* in Man, joining the anterior 



int- rosseoiis branches uf the fore-arm, an I <le.-ct mliiiL.' afterwards intti the interm. tacarj.al 



unite with the collateral arteries of the digit* at tho metucarpo-phaL 

 articiil ilii'iis. 



l;,i.i;,il Ki-l'fii: id radial of tho other nnimal-. Lying alongside the 



Mi-xor of tin- thumb and the |H rforans muscle, this artery follow- the inner faco of 



tin- p rt'oiatu.- iiiii-, 1., ami curving outward* t> be united to a uianch fiom the posterior 



antibrachial inteio-.-i ,,u.- art. ry. forms the any rjl<-;,il ^nJiiinr (/'/./.. from whieii escape 



