TIII-: nit. iriii.ii. 



.\\n.i.\n\ i /,/'/; /,-//>. 





meiatar.-al span .-. \s itli the plantar int. m>-. ni> trterifll l-v the Onfer/OI and /<*/. </. 

 inrjin-nlniij ni-li-,-;,.< : linally. ill ill-- }>n-<- nt' the t.-es llicy liii'uresile to !'.! In the ,WM. , ,./ 



<;/' // foe. 

 Tlir <lrf<tl rnllnti i-ii! arti ;// nf tin' joiirtli KJHI/-I i. |.i. -, nt- 



tin- vessel deseriKed ill tile ||oi>" l.y tile name of llietatarSO- Fi','. 281. 



iters, "r collateral of the cunnoii ; it forms the in- 

 ternal collateral dorsal of the fourth toe, and external collateral 



nf llle L;rellt toe. 



./<.,-MI//X y,.//M, afle.r t^ivill^ nft' the last-nain 

 lijis inti) the fourth spa-, and reaches the lower surfac^ "I 

 the font, where itainistonioses with the internal plantar artery. 

 In tliU l:i t t portion of its course it resembles tin vessel we 

 liiive named tiie perforating pulal in 



ARTICLE V. ANTERIOR AORTA. (Fig. 282, 1.) 



This vessel, the smallest of the two trunks suc- 

 ceeding the common aorta, is no more than 2 or 2 

 inches in length at tho most. It leaves the pericar- 

 dium to pass between the two layers of the medias- 

 tinum in an oblique direction from below upwards 

 and In-hind forwards, above the right auricle, below 

 tho trachea, and to the left of the anterior vena cava. 

 After furnishing some insignificant twigs to the 

 pericardium and mediastinum, it divides into two 

 branches which constitute the brachial trunks or 

 ii.rilltir// arteries. 



In the Pachyderms and Carnivora, the anterior 

 aorta does not exist, and the axillary arteries arise 

 directly from the aortic trunk, towards the point 

 from which the anterior aorta springs in other 

 animals. 



ARTICLE VI. BRACHIAL TRUNKS OR AXILLARY 



ARTERIES. (Fig. 282, 2, 3.) 



Tho brachial trunks, terminal branches of the 

 anterior aorta, are distinguished into left and right. 

 Tho latter is much larger than the former, because 

 it furnishes the arteries of the head. It is also 

 named the brachto-cepkalic trunk (or arli-rin innnmi- 



ARTERIES OF SOLE or 

 II r MAN FOOT. 



I'lider surface of os ral- 



ris : '_', Mtisrulii.- . 



soi ins ; .i, Loii}; flexor 



tendon-,; I. Trillion of 



peroneus longus ; 5, Ter- 



minatiou of posterior 

 tiliial artery; G, Internal 

 plantar ; 7. Kxternal 

 plantar ; S. I'lantar areh 

 tfivin-; off four digital 

 iininrlies, three of which 

 are seni dividing into 



tV/tn. They separate from one another at an collaterals for adjoining 

 acute angle, the left being a little more eh vated 

 than the right. 



C"H /-.- "/"'' ilirtrfion. Both branches are directed forwaids. between t' < 

 lamina* of the anterior mediastinum and beneath the trachea ; gaining the 

 entrance to the chest, and leaving it by turning round the anterior border 

 of the first rib, under the insertion of the scahnus, they become inlleeti d 

 backwards and downwards, to bo placed, one to tho right, tho other to tin- 

 left, at the internal face of the anterior limb, in the middle of the nervous 

 braiii-h.-s of the brachial plexus, and continue within the arm, assuming tin- 

 name <>f Immcral artery on leaving tho interstice which separates the sub- 

 scaptilai is muscle from the adductor of tho arm. 



In its thoracie course, tho left trunk describ, s u curve u ivexity 



is upwards, the right taking a rectilinear direction. 



/.' Idtlniix. - In studying tho relations of the brachial trunks, we iec. 

 two principal portions: one thoracic, placed in the chest; tho other axillary. 



