THORACIC NERVES. 5 
skin of the front of 
the chest, over an area 
i See. 
corresponding to the Ra) SS wy 
inner or anterior part \" a) 
of the intercostal | eas 
space to which it be- 
longs. 
Branches. — Each 
intercostal nerve 
supplies, in addition 
to the anterior _ ter- 
minal cutaneous 
branches, muscular 
branches to the inter- 
costal muscles and a 
lateral trunk (r. cut- 
aneus lateralis), which, 
piercing the intercostal 
muscles and the ser- 
ratus magnus, divides 
into anterior and 
posterior branches for 
the innervation of the 
i 
skin over the side of H 
the chest. Each area of Anterior | 
skin thus innervated is Bre as aa 
5 : Later 
continuous anteriorly 8 \ Branches 
with the area inner- 
vated by the anterior 
terminal branches of 
the same nerves, and 
posteriorly with the 
areas supplied by their 
posterior primary divi- 
sions. 
The upper six inter- 
costal nerves supply 
the muscles of the first 
six intercostal spaces y 
and the triangularis Qy L.2.5 
sterni (3,4,5,6). The 3 
second, third, fourth, x 
fifth, and sixth nerves S 
~ 
supply the skin of the 
front of the chest: the 
second, opposite the 
manubrio-sternaljoint; Fic. 438.—Tue Disrrrsurron or Curanrous NERVES ON THE FRONT OF 
the sixth, opposite the DHE PRONE. 
base of the xiphoid car- On one side the distribution of the several nerves is represented, the letters 
tilage. Their lateral indicating their nomenclature. 
branches supply the G.A, Great auricular nerve; S.C, Superficial cervical nerve ; 8.CL, Supra- 
clavicular nerves ; AcR, Acromial ; Cr, Clavicular ; St, Sternal ; T.2-12, 
skin of the side of the Lateral and anterior branches of thoracic nerves ; I.H, Iio-hypogastric 
chest, the second (in- nerve ; I.I, Ilio-inguinal nerve ; C1rc, Cutaneous branch of circumflex 
te pe Se nerve ; L.I.C, Lesser internal cutaneous nerve ; I.H, Intercosto-humeral ; 
tercosto-humer al) and 1.0, Internal cutaneous ; M.S, Cutaneous branch of musculo-spiral nerve ; 
the third in part being E.C, External cutaneous nerves ; G.C, Genito-crural nerve ; M.C!”, Middle 
drawn out on to the cutaneous nerves; I.C!, Branch of internal cutaneous nerve ; P, Branches 
of pudic nerve ; 8.Sc, Branches of small sciatic nerve. 
arm ihe “fourth ‘ 
supplies the nipple On the other side a schematic representation is given of the areas supplied by 
: is the above nerves, the numerals indicating the spinal origin of the branches 
(Fig. 438). of distribution to each area. 
