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12 THE BLOOD-VASCULAR SYSTEM OF THE OX 
The radial artery is the smaller of the two terminal branches of the median. It 
descends on the flexor carpi radialis, passes over the medio-volar surface of the 
‘arpus, and is continued as the medial deep volar metacarpal artery. At the distal 
end of the forearm and at the carpus it furnishes branches to the retia carpi. An- 
other branch (A. met. perforans proximalis) runs outward between the suspensory 
ligament and the large metacarpal bone, passes through the proximal foramen of 
the bone, and unites with the dorsal metacarpal artery; before passing through the 
foramen it detaches the middle deep volar metacarpal artery (A. met. volaris prof. 
III.). This descends on the volar face of the metacarpal bone, receives an anasto- 
motic branch from the medial deep artery, and concurs in the formation of the deep 
volar arch above the fetlock. The medial deep volar metacarpal artery (A. met. 
volaris prof. II.) descends along the medial part of the volar surface of the large 
metacarpal bone and is continued as the medial volar proper digital artery. At the 
distal part of the metacarpus it is connected by a transverse branch with the middle 
deep volar metacarpal artery, and similarly with the volar common digital, forming 
with the latter the superficial volar arch. 
The ulnar artery, the larger of the two divisions of the median, descends under 
cover of the flexor carpi radialis without giving off any large branches in the fore- 
arm. It passes through the carpal canal and continues along the medial side of the 
deep flexor tendon as the volar common digital artery (A. met. volaris superficialis 
IIl.). At the distal third of the metacarpus this vessel is joined by a branch from 
the medial deep volar metacarpal artery, forming the superficial volar arch. Near 
this another branch of the common digital (or of the medial digital) passes around 
the lateral border of the flexor tendons to the posterior face of the metacarpal bone 
and concurs with the deep volar metacarpal arteries in the formation of the deep 
volar arch. A branch from the arch (A. met. perforans distalis) passes forward 
through the distal foramen of the metacarpal bone and joins the dorsal metacarpal 
artery which descends from the rete carpi dorsale in the dorsal metacarpal groove. 
The volar common digital artery (A. metacarpea volaris superficialis III.) 
passes into the interdigital space and divides into two volar proper digital arteries, 
which descend along the interdigital surfaces of the chief digits and pass through 
the foramina at the proximal part of the interdigital surfaces of the third phalanges, 
enter the cavities in these bones, and ramify in a manner similar to the correspond- 
ing vessels in the horse. The volar common digital detaches a branch (A. inter- 
digitalis perforans) which passes forward through the upper part of the interdigital 
space and anastomoses with the dorsal metacarpal artery. 
The volar proper digital arteries (or the common digital) give off, in addition to other col- 
laterals, branches which correspond to the arteries of the digital cushion of the horse. These 
pass to the bulbs of the claws and anastomose with each other and with the medial and lateral 
digital arteries, forming an arch from which numerous branches are distributed to the corium 
of the hoofs. 
The dorsal metacarpal artery (A. met. dorsalis II.) is a small vessel which 
arises from the rete carpi dorsale, descends in the groove on the dorsal face of the 
metacarpal bone, and is joined by the distal perforating metacarpal artery from 
the deep volar arch to constitute the dorsal common digital artery. This vessel 
(A. digitalis communis clorsalis III.) divides into two dorsal proper digital arteries. 
The medial volar digital artery (A. digiti III. medialis) is the continuation of the 
medial deep volar metacarpal artery. It descends on the medial side of the medial 
digit and terminates at the bulb of the claw by anastomosing with the corresponding 
volar proper digital artery. It gives off a branch to the rudimentary digit and 
forms a transverse anastomosis behind the first phalanx with the volar common 
digital or its medial division. 
The lateral volar digital artery (A. cigiti IV. lateralis) arises from the deep volar 
