SUPERFICIAL DISSECTIONS 25 



latter of which has already been followed. The former passes from front 

 to back of the tarsus through the canal formed between the cuboid, 

 scaphoid, and cuneiform magnum, and assists the plantar arteries in 

 forming the arterial arch of the tarsus. 



The posterior tibial artery first becomes visible in the Plate where 

 it makes its appearance from beneath the flexor accessorius. It here 

 lies on the flexor perforans muscle. It runs down the limb on the 

 last-named muscle, and is crossed by the posterior root of the internal 

 saphena vein, and also by the cutaneous branch of the posterior tibial 

 nerve. 



Just above the hock it forms a peculiar S-shaped curve, and from the 

 second portion of this curve a retrograde braitch is given oif which ascends 

 the limb in front of the posterior tibial nerve. 



The artery then divides into the external and internal plantar 

 vessels. These accompany the perforans tendon through the tarsal 

 sheath, and contribute to the formation of the arterial arch referred 

 to above. 



From this arch four branches are given off. Two of these run down 

 the limb, one on either edge of the suspensory ligament, being placed 

 between the ligament and the small metatarsal bones. These are the 

 Plantar Interosseous Arteries. The outer anastomoses with the small 

 recurrent branch of the large metatarsal artery, and the inner, which 

 gives off the nutrient artery to the large metatarsal bone, unites with the 

 large metatarsal artery itself. 



The remaining branches of the arch are the two small unnamed vessels 

 which accompany the plantar nerves. The inner one is represented in 

 the Plate. 



The arrangement and distribution of the arteries and veins, from the 

 fetlock downwards, conform to the description given of the correspond- 

 ing vessels on the outer aspect of the limb. 



D 



