870 TRE NERVES. 



internal digit ; the third givcB some filaments to the ergot, and passes along the digital region, 

 where it constituted the internal collateral of the internal digit. 



Pig. — Three fasciculi are detached from the brachial plexus; the posterior is the most 

 voluminous, and furnishes the radial, median, and ulnar. 



Tiie branches of the plexus that paas to the trunk and the first segments of the anterior 

 limb much resemble those of Euminants; the branch of the serratas magnus is remarkable for 

 its length and size. 



The median nerve is disposed like that of Solipeds and Ruminants, as far as the carpus-, 

 from this point it passes beneath the flexor tendons of the phalanges, gives filaments to the 

 interosseous palmar muscles, and at the two rudimentary digits divides into four branches: 

 the two upper are the smallest, and forms the collaterals of the rudimentary digits; the 

 Inferior two are the longest, and reach tire principal interdigital space, forming the collaterals 

 of the two great digits. 



The ulnar gives oflf, towards the middle of the arm, a branch that passes to the ulna ; at 

 the ulnar it furnishes several muscular branches. The nerve then bend round to the outside 

 of the forearm, and on arriving above the pisiform bone, bifurcates : one branch goes along 

 the outer border of the flexor tendons, and is continued by the collateral of the external digit; 

 the other is placed on the anterior face of the metacarpus, and also bifurcates to give the 

 external digits their dorsal collateral nerves. 



Carnivora. — The four last cervical and first dorsal compose the brachial plexus in the 

 Carnivora; the fifth cervical gives an Risignifieant filament. Whenthe plexus is unravelled, 

 its principal brandies are observed to send fibres to each other. 



The number of the distributive branches is the same as in Solipeds, and the disposition of 

 the superior branches is so analogous as to call for no remark ; so we will only describe the 

 anterior brachial, radial, median, and cubital nerve. 



The anterior brachial, or muscalo-cutaneous, is constituted by a filament from the sixth 

 cervical and the more voluminous branches coming from the seventh. Placed in front of the 

 axillary artery, this cord arrives at the scapulo-humeral articulation, where it bifurcates : one 

 of the branches passes forward to the biceps ; the other remains alongside the anterior border 

 of the humeral artery, and terminates by a slightly recurrent branch that is buried in the 

 anterior brachial muscle, and by a very fine filament that becomes subcutaneous at tlie elbow, 

 and descends on the inner border of the foreariu to be lost in the vicinity of the carpus. The 

 anterior brachial is, therefore, in these animals, a musculo-cutaneous nerve. The branch 

 uniting ic to the median nt-rve is situated a little below the middle of the humerus, instead 

 of being beneath the axillary artery, as in Solipeds. 



The radial nerve, in the Dog, is exclusively formed by the eijrhth cervical ; it receives 

 filaments from the median, ulnar, and axillary nerve, and gives branches to these three. When 

 it reaches the interstice of tiie triceps and anterior brachial, it crosses the limb above the outer 

 face of the elbow, and divides into two series of terminal branches. 



The muscular branch enters beneath the muscles on the anterior face of the forearm. 

 The cutaneous bifurcates immediately : the smallest branch, passing inwards, extends beyond 

 the bend of the elbow, lies at the inner border of the median subcutaneous vein, and is dis- 

 tributed to the lower moiety of the forearm, the thumb, and internal border of the index digit. 

 The largest lies at the outer side of the median subcutaneous vein ; it sends a recurrent 

 ramuscule to the bend of the elbow, and, at the elbow, detaches three filaments to the first, 

 second, and third dorsal intermetacarpal spaces ; these filaments bifurcate at the dorsum of the 

 digits to constitute the collateral dorsal nerves. The first metacarpal nerve anastomoses, by a 

 fir transverse branch, with the ulnar ramuscule that constitutes the external dorsal collateral 

 of the small digit- 



To resume : the radial of the Dog gives branches to the dorsal face of all the digits, except 

 the external border of first digit, or auricularis. 



In the Cat, there are some difltrences. The internal branch of the radial sometimes 

 lies with the external branch ; it is placed at the inner border of the metacarpus, gives oft' a 

 filament to the dorsal face of tiie thumb, and afterwards forms the internal dorsal collateral 

 nerve of the index. The external branch leaves the anterior face of the carpus, and is situated 

 at the origin of the third interosseous space, whtre it divides into three metacarpal branches; 

 the external of these is very fine, and directed obliquely outwards, anastomosing with the 

 dorsal branch of the ulnar, between the first and second digits. 



The median of the Dog is united to the ulnar as far as the lower fourth of the arm ; it is 

 situated behind the humeral ajtery, and the filament it receives from the musculo-cutaneous 

 joins it at a short distance from the elbow-joint. Placed btside the radial artery, the median 

 is, towards the lower third of the forearm, immediately below the posterior border of the 



