'////: i.r.Mii.ii; .V//.M Bfi 7.1 1 



ascends towards tin- summit of tin- spin- .us pr.<cessos of the dorsal 



vTtebr;i'. ],: p;is-.ing between the semispinalis and longissimus dorsi ; 



the other is directed outwards, in traversing the substance of the latter muscle. 



;ion BRANCHES. These are more considerable in size than tho 



Hug, and descend into the intercostal spaces, between the pleura and 



the internal intercostal muscles, or even in the texture of these. With tho 



exception of the first, whoso arrangement is different, they all pass at first 



"\vr the head of the posterior rib to roach the convex border of the anterior 



one, and follow it to the extremity of the intercostal space. 



There they terminate in the following manner: those of the sternal 

 ribs traverso tho pectoral muscles, giving filaments to these, and are 

 expended in the skin of the subthoracic region. Those of the asternal 

 ribs enter the abdominal muscles, passing between the transversalis and 

 ivetns ahdomiuis ; they also give cutaneous filaments to the skin of the belly. 



Near their origin, the inferior branches communicate with the great 

 sympathetic, for the most part, by several filaments. 



In their course they furnish numerous fine ramuscules to the intercostal 

 muscles, and, in addition, give off, about the middle of their length, a very 

 thick division the perforating intercostal branch, which traverses the costal 

 muscles and des 'ends beneath the panniculus carnosus, ramifying partly in 

 that muscle and partly in the skin. The most anterior perforating branches 

 generally anastomose with the subcutaneous thoracic branch of the brachial 

 plexus. 



With regard to the first dorsal pair, its inferior branch enters the latter 

 plexus ; but it nevertheless furnishes an intercostal branch, always extremely 

 slender, which passes over tho external intercostal muscle to be expended 

 in its substance before arriving at the sternum. The second pair also concurs 

 in the formation of the brachial plexus, though only by a small branch. 



Aimcu: III. LUMBAIJ NKKVES (G Pairs). 



SCPEUIOK IJitAM-iiKs. Destined to the spinal muscles and the integu- 

 ments <>f the loins and croup, these are larger than the corresponding 

 branches of the dorsal region, and present an analogous disposition ; they 

 give superior ramuscules to the muscles of the spine, and very long external 

 divisions which pass through these muscles to be distributed to tho skin of 

 tho croup. 



:;IOK BUAXCHKS Tho/i*W, comprised in tho interval separating tho 

 last rib from the first lumbar transverse process, between the quadratus 

 lumborum and the psoas magnus, passes downwards and backwards until it gets 

 between the transverse and internal oblique muscles of the ahlnni- n. t > which 

 it gives filaments, and is finally distributed in the great rectus mu.-cle. 



Above tho superior border of the internal oblique muscle, it furnishes a 

 perforating branch to tho skin of tho flank and tho posterior pait of tho 

 panniculuB carnosus. 



Tho second, disposed in the same manner as the preceding, follows an 

 analogous course, and breaks up into several divisions which arc lost in 

 the small oblique muscle. From one of these sometimes emanates a slender 

 filament, which joins one of the inguinal nerves of tho third pair. Wo 

 must not overlook, in the enumeration of the branches emitted l.y this 

 second pair of lnmi*.r nerves, the two perforating branches which 1< 

 in front, and on tho inside, of tho-thigh, to Ix; distributed to the sk : n of the 

 flank and the internal crural region. 



