THE LIMBS OF THE HORSE 



151 



metatarsal arteries, of which the medial is the larger, run down the 

 metatarsus in the depths of the grooves formed by the middle inter- 

 osseous muscle and the small metatarsal bones, and end by uniting 

 with the common digital artery, thus forming the distal plantar arch 

 (arcus plantaris distalis). The medial artery furnishes the nutrient 

 vessel for the third metatarsal bone. 



On its passage between the third and fourth metatarsal bones 

 the lateral dorsal metatarsal becomes the common clicjital artery 



M. gastrociieniius. 



Tuber calcanei. 



Talus. 

 Sustentaculum tali. 



Central tarsal bone 



(soaplioi(l). 

 M. tibialis anterior. 1/ 



First tarsal bone. 

 Second tarsal bone. 



Second metatarsal l)one. 



Third metatarsal bone. 



Fourth tarsal bone (cuboid). 

 %4---. M. fle.xor digitorum profundus. 



Fourth metatarsal bone. 

 - M. iuterosseus. 



Fig. 104. — Plantar (Posterior) Aspect of the Tarsus, with Areas of JMuscular Attachment. 



(a. digitalis communis), which traverses the gap between the two 

 limbs of the interosseous muscle and, between this and the deep 

 flexor tendon, divides into the medial and latercd plantar digital 

 arteries. The digital arteries have a distribution similar to that 

 of the corresponding vessels of the thoracic limb. 



Veins of the metatarsus and digit. — The plexuses and veins 

 of the digit are similar to those of the thoracic limb, the two digital 

 veins, medial and lateral, being joined in the formation of a distcd 

 plaiitar venous arch (arcus venosus plantaris distalis). 



There may be six veins in the metatarsus, but of these three are 



