SUPERFICIAL DISSECTIONS 19 



Above the hock it will be seen on the inner aspect of the limb, where 

 it forms the smaller of the two roots of the internal saphena vein. 



The Nerves 



The External Saphena Nerve (6). — This is a branch of the great 

 sciatic nerve. It is given off from the latter at a point which varies 

 from two to six inches from the place where it dips between the two 

 heads of the gastrocnemius muscle. 



It passes along the external aspect of the outer head of the muscle 

 named, and receives a reinforcing branch (8) from the external popliteal 

 nerve. This branch leaves the external popliteal above the stifle, and 

 runs downwards and backwards across the gastrocnemius muscle. 



The external saphena nerve continues its course down the limb in 

 front of the tendo-achilles, and gives off cutaneous branches, which are 

 distributed on the outer lateral aspect of the hock. The nerve usually 

 terminates in the skin about midway between the hock and fetlock, but 

 occasionally it is continued much lower down the limb, to be distributed 

 to the skin covering the phalanges. 



The External Popliteal Nerve (5). — This nerve is a branch of 

 the great sciatic, from which it is given off almost immediately after 

 the latter leaves the pelvic cavity. It runs obliquely downwards and 

 forwards, and passes between the biceps femoris and the outer head of 

 the gastrocnemius. The former muscle having been removed, the 

 nerve is first visible in the Plate where it lies on the gastrocnemius. 



Immediately below the point of detachment of the communicating 

 branch to the external saphena nerve, this nerve gives off its peroneal- 

 cutaneous branch. The latter nerve runs along the inferior border of 

 the biceps femoris, and splits up into a number of branches, which are 

 distributed to the skin in front of the stifle and the leg. The peroneal- 

 cutaneous nerve being more superficially placed, is not represented in the 

 Plate. 



