46 



under the M. peroneus to which it supplies small branches; it also gives 

 of? a cutaneous branch. 



A. plantaris medialis and A. plantaris lateralis. 



These two small terminal branches of the tibialis posterior vary some- 

 what in different specimens. The following disposition however is common. 

 Each plantar artery descends with the respective plantar nerves, on either 

 side of the perforans tendon, to the proximal part of the metatarsus where, 

 between the flexor tendon and the suspensory ligament, they unite with the 

 A. tarsea perforans to form the arcus plantaris or plantar arch. The flexor 

 tendons should be cut and tinned aside. Sometimes the A. plantaris 

 medialis does not join the plantar arch but is continued as the small satel- 

 lite vessel of the N. plantaris medialis. Four plantar metatarsal arteries 

 originate from the plantar arch. The two small superficial arteries, meta- 

 tarsea plantaris superficialis medialis and lateralis accompany the plantar 

 nerves on either side of the flexor tendons and unite with the A. metatarsea 

 dor sails or with the corresponding digital arteries. Sometimes, as men- 

 tioned above, one of the superficial plantar metatarsal arteries is the direct 

 continuation of the A. plantaris medialis. Transect and draw aside the 

 suspensory ligament. 



The two deep plantar metatarsal arteries, Aa. metatarsea plantaris 

 profundus medialis and lateralis, descend between the suspensory ligament 

 and the corresponding rudimentary metatarsal bones and unite near the 

 fetlock with the A. metatarsea dorsalis. Of the two deep metatarsal 

 arteries the medial or internal one is much the larger and supplies the 

 nutrient artery to the large metatarsal bone. 



A. tarsea perforans arises from the A. tibialis anterior, passes through the 

 tarsal canal and unites with the plantar arteries or with the external one 

 only, to form the plantar arch. 



A. metatarsea dorsalis (lateralis) is the direct continuation of the A. tibialis 

 anterior. It crosses the anterior surface of the tarsal joint and descends, 

 at first, in the oblique vascular groove on the lateral face of the proximal 

 part of the principal metatarsal bone and then in the groove formed by 

 the principal and the lateral rudimentary metatarsal bonesi Near the 

 distal end of the rudimentary metatarsal the artery passes between the 

 two bones and divides on the posterior face of the principal metatarsal, 

 between the two divisions of the suspensory ligament, to form the A. digitalis 

 medialis and the A. digitalis lateralis. These two arteries and their branches 

 are similar to those of the thoracic limb. 



