<'KIM<;i',i;o-snN \l, \h.i;VKS. 



in thi- fool, to the whole hivudtli of the solo. The lil'lh luml>;ir uer\e docs no! 

 hceome etilaneoiis on I he vein ral aspect mil d the sole is reached, hut in I he dorsal 

 nerves it, appears earlier in the lateral cutaneous hraneh ofilie peroneal. 'The toes 

 are supplied l>y the fourth and lil'lh luinhar, and I he first, and second sacral nerves, 

 in this order, from the preaxiul to the postaxial side. 



The disposition ..I' (he cutaneous arras of I lie segment a 1 nerves in the Innli. as determined 

 1V Sherriii I on for I lie pelvic liniti ot' I lie monkey, is shown dia: 1 ramniat iea 1 1 v in tiy.'J'JI. The 

 .e\ era I tie Ids are seen to lie arranged in^ regular order a Ion L; a line continued out wards from the 

 dorsal or vent ral median line of I lie t rim k, over t he correspond iny surface of I he limb, and form- 

 ing a kind of secondary axial line for the latter. The lields of I he preaxial nerves eoiist.il n I e 

 i de ccndm:' series almi" this line, the sixth Inmhar field spreads from the end of the axial 

 line to the extremity of the limit, and the lields of the postaxial nerves, less numerous 

 than the preavial, form an ascending series. The arranycment of the cutaneous nerves does 

 not a",ree with thai of the mol or ner\ es of I he limh, \\hich supply each a coiititrnoiis band 

 rn nn i n L; pa ral lei lo i he limit-axis from the I rnnk to I he free Itorder of I he limit. The in use I es 



of a given part of the limb and the overlying integument are, therefore, not necessarily 



supplied l>v t he same se^ineutal nerves ( SherriuL;'tou ). 



I 'i". tires L'l'.'i. 'J'Ji'i ami !"_' 7 represent, (he se-.- mental areas" of tlu> skin oxer the trunk and 

 limits as determined hy Head from clinical observations. These areas are. however, not the 

 re;/ ions supplied by the respective posterior spinal nerve roots, but represent rat her the parts 

 of the skin in connection with the segments of the j^rey matter of the spinal eord by means 

 ,if lib res subserving the sensations of pain, heat, and cold, but not. touch. They differ 

 --I rikin; 1 ,! \ from the areas of the posterior nerve roots in not overlapping, except to a small 

 extenl in (he neck and upper limbs, whereas I he root areas overlap so much that there is no 

 loss of tactile sensation after division til a single posterior root. ( Sherrinv.ton, Head). II ma\ 

 also be pointed out thai the areas as designated by Head do not always ai;rec with the distri- 

 bution of I he corresponding ner\e- as determined anatomically. Thus, the area marked 1> .'i 

 on the inner side of the arm corresponds rather to I he brachial (list rilmt i< -n of t he second 

 dorsal iierxe through its mlcrcosto- humeral branch and the communication with the nerve ol 

 \\rishep.'.. while the third dorsal nerye does not usually contribute largely to the supply of the 

 arm. Similarlv, I he areas marked I) II. I) !'_', and I/ I, would seem on anatomical ; rounds, :>s 

 well as from observations in cases of injury, as shown by Thorburu. to correspond more 



nearly to the twelfth dorsal and first and second lumbar nerves, it is therefore possible thai. 



while the !',d ici a I a rran " men I anil distribution of the sey.'inental areas, as well as their 

 visceral associations, have been in principle correct ly IVCOL: n i /ed by Head, some modifications 

 in the details of limitation and enumeration of these areas mav be rendered necessary by more 

 extended ohservat ions. 



SENSORY DISTRIBUTION OP THE SPINAL NERVES TO THE VISCERA. 



There is strong reason for believing thai the tlioracie and abdominal viscera are supplied 

 \\ith sensory t-hres derived from the spinal nerves, and passing through the sympathetic. In 

 IliedoLT Kd;;vwort h has traced mednllatcd fibres of medium si/.e. which he regards as sensory. 

 Irotii the posterior roots of the spinal nerves into the s\ mpat het ic. and thence to the several 

 viscera : and his results are ^cncralh in close agreement with the inferences drawn 

 from clinical observations in man (Head), although their accuracy in some particulars is 

 disputed by l,ani;-ley. Kolliker also recoL>;ni/,cs mednllatcd sensory nerve libres passing without 



interruption from the posterior roots of spinal nerves through the sympathetic to the 

 viscera. Indirect evidence as to the source of these fibres is furnished by the seat of 



"referred pain' in alVcctiotis ol the several organs. Arrordin:; to the hypothesis of Ross. 

 the pain is referred in such cases to part s supplied hy somatic sensory libres having t heir origin 

 t rom the nerves in which the sensory fibres of the a Heeled \iscusare contained, owiniv 

 to dilVnsion of the irritation conveyed by the latter libres in the corresponding segment of the 



grey matter of the spinal cord. The following table, taken from Head, shows the probable 

 origin of the sensory fibres of the different organs : 



Heart.-l. _'. :i dorsal. 



Lnnirs. 1. _'. 3, I. I dot-sal. 



Stomach. ('. 7. *. !> dorsal. Cardiac end from ('. 7. 1'yloric end from !>. 



Intestines. (n) Down to upper part of rectum, D. lo. n. 12 dorsal. (A) Rectum. _'. ::. ! 



sacral. 



Liver and ( iall-l'daddcr. (\\ .'), 7, S, . 10 dorsal. 



Kidney and Ureter.10, 11, 12 dorsal. Upper part of ureter, 10 dorsal. At lower end ol 



ureter. 1 lumbar tends to appear. 



Bladder. () Mucous membrane and neck of bladder, (1), 2, 3, 4 sacral, (ft) Over- 

 distension and inett'ectual contract ion. 11. 1 L' dorsal, and 1 lumbar. 



