DISSECTION OF THE POSTERIOR LIMB. 71 



joint and the common insertion of the iliacus and psoas magnus intact 

 for examination by the dissector of the abdomen and pelvis. The limb 

 having been removed, it should be placed on a table, and the cut 

 muscles connected with it may be completely cut away after they 

 have been identified. In doing this, a better opportunity will be 

 afforded to observe accurately the insertion of each muscle. In remov- 

 ing the lower portion of the biceps, particular care must be taken not 

 to cut the external popliteal and external saphenous nerves, which 

 are included between it and the outer head of the gastrocnemius 

 (Plate 18). 



THE LEG. 



Surf ace-marldng.— The bones of the leg are clothed by muscles except 

 at the inner side of the limb, where the tibia is subcutaneous. This 

 unprotected area of bone corresponds to the shin in man. The super- 

 ficial muscles of the region {see Plates 17 and 18) form prominences 

 more or less distinct, especially in the neighbourhood of the hock, where 

 the various tendons stand out distinctly during the movements of the 

 living animal. 



Position. — In the further dissection of the limb, it may' be placed on a 

 clean table, and laid on either side as may be convenient ; or a cord 

 may be passed round the femur, and the limb suspended at such a 

 height as just to permit the hoof to come into contact with the table. 

 This latter method has the advantage of keeping the part clean ; and, 

 while dissection is being carried on, the leg may be steadied in any 

 position by an assistant. 



Directions. — An incision through the skin is to be carried down the 

 middle line of the limb on its inner side, and terminated a few inches 

 below the hock, where a circular incision may be carried round the 

 limb. The whole of the skin above the circular incision is then to be 

 removed, and the cutaneous nerves and vessels of the region are to be 

 examined. 



The Internal Saphena Vein. On the inner side of the leg, above 

 the hock, two venous branches will be seen to converge and unite to 

 form the internal saphena vein, which is continued up the leg to the 

 thigh, where it has already been dissected. The vessels by whose union 

 the main vein is formed are the upward continuations of the internal 

 and external metatarsal veins. Slender branches of the saphena artery 

 accompany these veins. 



The External Saphena Vein, This vessel begins at the hook, where 

 it communicates with the internal saphena vein, and with the posterior 

 tibial vein. It ascends at the outer side of the gastrocnemius tendon, 

 and, passing between that muscle and the biceps, it empties itself into 

 the femoro-popliteal vein. 



