882 TEE NERVES. 



lumbar vertebra and the sacrum. The plexus may be divided into two povtinns. the first 

 furnishing a femoral and an obturator nerve. The internal saphenic branch of the femoral nerve 

 is lone and voluminous; at its origin it is as large as the branch }ia8sinK to the anterior 

 muscles of the thigh, and it descends on the inner face of the metatarsus, forming the dorsal 

 collateral of the internal digit. 



The great sciatic is voluminous and round. The branches it gives to the muscles of the 

 pelvis and femur are disposed nearly as in Solipeds and Kuminants ; but differences are 

 observed in the external popliteal and the terminal branches. 



The musculo-cntaneous nerve reaches the metatarsal region, where it separates into three 

 branches, which form the dorsal collaterals of the digits. 



Tlie anterior tibial nerve descends between the two principal metatarsals, and at the root 

 of the middle digits divides to anastomose with the plantar nerves. Of these the external is 

 small, and gives collaterals to the two external digits; the internal, the largest, descends 

 between the two principal digits, where it bifurcates; above, it gives a branch to tiie internal 

 digit. 



Carnivora. — In these animals, the lumbo-sacral plexus is formed by the last four lumbar 

 and the first two sacral. 



The crural and obturator nerves, which arise from the fourth, fifth, and sixth lumbar nerves, 

 offer nothing particular in their disposition. 



The internal saphenic branch is as long as in the Pig; it passes to the internal face of the 

 tarsus, lies alongside the fourth metatarsal bone, and forms the internal dorsal collateral of 

 the fourth toe. 



The great sciatic may be described as having, as in Man, two terminal branches which 

 separate a little above the posterior face of the femoro-tibial articulation. The external 

 popliteal nerve passes to the surface of the external gastrocnemius, enters between the common 

 long flexor of the toes and the long lateral peroneal muscle, where it bifurc;ites. The musculo- 

 cutaneous branch descends beneath the latter muscle to the lower third of the leg, when it 

 becomes superficial, and, accompanied by a vein, is lodged in the interspace between that 

 muscle and the anterior tibial ; it passes in front of the tarsus, and reaches the upper part of 

 the metatarsus, where it divides into three divisions. It must be mentioned that at the tibio- 

 tarsal articulation is thrown off a very fine cord, which is directed outwards, and forms the 

 external dorsal collateral of the first toe. Each of its three terminal branches courses 

 along an intermetatarsal space, and at the metatarso-phalangeal articulations separates into 

 two filaments, whence results the following distribution: the external branch forms the 

 internal dorsal collaterals of the first toe and external of the second ; the middle constitutes 

 the internal dorsal collaterals of the second toe and. external of the third; lastly, the internal 

 furnishes the internal dorsal collaterals of the third toe and external of the fourth. The 

 anterior tibial nerve accompanies the artery of that name, descends along the external face of 

 the tibia, and terminates in two branches at the tarsus. Of these, one is distributed to the 

 tarsal articulations and the pedal muscle: the other, internal, enters the intermetatarsal 

 space, and at the corresponding metatarso-phalangeal joints anastomoses with the internal 

 branch of the musculo-cutaneous nerve, and is lost in the same parts. Tiie internal popliteal 

 forms the second terminal branch of the great sciatic nerve, and in the Dog and Cat repre- 

 sents that portion of the latter which, in the Horse, is situated behind the femoro-tibial 

 articulation. It is continued by the posterior tibial nerve, which terminates by the two 

 plantar nerves. During its course, the external popliteal furnishes articular and muscular 

 filaments, as well as cutaneous twigs subsequently ; among the latter may be mentioned the 

 external saphenic, which arises by two brandies, and is expended behind the malleolus, at the 

 outer side of the tarsus. The plantar nerves are external and internal ; the latter lies at the 

 inner border of the tendon of the superficial fiexor muscles of the phalanges, and when it 

 joins the middle of the metatarsus, it detaches a fine filament that forms tlie internal plantar 

 collateral of the fourth toe ; it then passes obliquely towards the first toe, at the deep face of 

 the above-named tendon, and successively gives off three filaments— one for each intermetar 

 tarsal space. These filaments anastomose with the terminal branches of the external plantar, 

 at the metatarso-phalangeal articulations; the first two filaments supply the large cushion 

 of the paw. 



The external plantar nerve passes between the two flexor tendons of the toes, where it 

 gives a filament that constitutes the external plantar collateral of the first toe. It is after- 

 wards placed outside the deep flexor, then enters beneath the short flexor and divides into 

 several branches— muscular and digital. Each of the latter— three in number— passes into a 

 corresponding interosseous space and bifiurcates at the metatarso-phalangeal articulations, 

 receiving filaments from he internal plantar, and forming the following plantar collaterals : 



