THE GREAT SYMPATHETIC NERVOUS SYSTEM. 885 



tuberosity it divides into two branches — an inferior or periuenl, and a sujifiinr or dorsalu penit 

 nerve. The latter is placed on the dorsum of the penis, and reaches tlie mucous membrane of 

 the glans and prepuce ; the former does not go beyond the muscles aiid integuments of the 

 perineum. 6. The superior gluteal nerve. 7. Serve of the pyramidalig. 8. Nerve of the 

 superior gemellus. 9. Nerve of the inferior gemellus and quadrutm cruralis. 10. The uniall 

 sciatic, or inferior gluteal nerve, the inferior or fenjoral braueii nf which is very long, descend- 

 ing, as it docs, to the middle of the posterior face of the thigh, beneath the crural aponeurosis, 

 to the popliteal space, where it becomes superficial, and terniinates in the skin of the upper 

 portion of the leg. 



Tlie terminal branch of the sacral plexus forms the great sciatic nerve, the distribution of 

 whicli is the same as tliat of Carnivora. The collateral ramnscules of tlie great sciatic are the 

 branch of tlie long portion of the bicep:<; the semitendinosus and semimembranosus branch ; the 

 branch to tiie great adductor; and, lastly, that to the short portion of the biceps. It terminates 

 by the external and internal popliteal. 



Tl;e musculo-cutaneous and anterior tibial, continuations of the external popliteus, comport 

 themselves almost tlie same as in the Dog. They form dorsal collaterals to the third, fourth, 

 and fifth toes, as well ns to the second. 



The internal popliteal jiresents an external saphenous nerve that passes along the external 

 border of the foot, and has, in addition, a branch that ascends on the dorsum of that organ. 

 The external saphenous furnishes the dorsal collaterals to the first toe, and the external 

 collateral to the second. The posterior tibial nerve continues the internal sciatic in the leg ; it 

 terminates in the plantar nerves. The internal plantar furnishes tlie collateral nerves to the 

 fifth, fourth, and third toes, and the internal colbiteral of the second toe. The external 

 divides into three branches : the two superficial branches form the collaterals of the first toe, 

 and the external collateral of the second; the deep branch passes inwards, behind tlie inter- 

 osseous muscles, and is expended in those of the fourth space, after giving filiiments to the 

 oblique abductor of the large toe, transverse abductor, last two lumbricales, to the interosseous, 

 and very fine filaments to the articulations of tlie tarsus with tlie metatarsus. 



It will therefore be seen, that, in Man, the branches of the deep trunk of the external 

 plantar join those of the internal plantar, to form the eollateral nerves. 



CHAPTER III. 

 THE GREAT SYMPATHETIC NERVOUS SYSTEM. 



Preparation of the Great Sympathetic— T?te same subject ought to suffice for the prepara- 

 tion of this, as u-ell as for the pneumogastric and spinal nerves. After placing the animal in 

 the first position, the intestines nre removed, one of the posterior limbs cut oif, and the greater 

 portion of the os innominatuni cleared away by sawing through the symphysis pubis and the 

 neck of the ilium ; the dissection of all the abdonaino-pelvic portion of the system, and that of 

 the terminal branches of the pneumogastric nerve, is then proceeded vsith. The anterior limb 

 of the same side should be afterwards detached, the scapula having been previously sawn 

 across its middle part, and the thorax thrown open by the ablation of tlie entire costal wall, in 

 sawing through the sternil cartilages below, and the ribs above, at their superior extremity. 

 All the thoracic portion of the ganglionic nervous apparatus, and the pneumogastric nerves, 

 may then be prepared. Notiiing more remains to be accomplished except the dissection of 

 the sympathetic and the vagus nerve in the cervico-cephalic region, with that of the spinal 

 nerve ; this operation is not attended with any difficulty, and should be precluded by the extir- 

 pation of a branch of the inferior maxilla. It is useful to inject the arterie.s previously; as 

 then the filaments of the sympathetic that lie alongside the vessels of the different organs in 

 the abdominal cavity can be more easily followed. 



The f/recit sympathetic, also named the triaplaachnir si/stpm {airXavx^ov, an 

 intestine or viscus), because of its position and destination, is the nervous appa- 

 ratus of the organs of ve<?etative life. 



