A macroscopic study of the vascular system of the bovine hind limb claw.
The vascular organisation of the hind limb claws from clinically normal cattle was studied using plastic corrosion casts. The proper digital artery ran dorsodistally within the interdigital space and gave off a bulbar branch to the bulb, a plantar branch to the axial aspect of the wall and sole, and a coronary artery to the coronary margin and proximal wall. The artery entered the distal phalanx at the axial foramen, coursed through the nutrient canal as the terminal arch, and emerged at the abaxial foramen to anastomose with branches of the bulbar artery. During its interosseous course, the terminal branch gave off 6-8 primary branches which provided the arterial supply to the coronary margin, axial and abaxial wall, white zone and sole. The dorsal proper digital vein and axial and abaxial proper plantar digital veins drained all venous blood from the claw. Each of these large veins arose from numerous smaller veins which joined to form the venous networks of the coronary margin, wall, sole and bulb. A large arched vein passed through the coronary cushion and formed a connection between the superficial coronary venous plexus and the intra-osseous plexus of the distal phalanx. The axial and abaxial proper plantar digital veins were connected by a vessel through the bulbar cushion. At the same level, the axial proper plantar digital veins of the lateral and medial claw were connected to each other by a large vessel through the interdigital space, situated just proximal to the distal interdigital ligaments. This resulted in the presence of a complete distal venous arch along the plantar aspects of both claws. The parietal collecting veins drained most of the venous blood from the sole, white zone and wall, and connected directly to the venous plexuses of the coronary margin and bulb. Valves occurred commonly in medium and larger calibre veins throughout the claw.
Vermunt
J J
JJ
Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Sask., Canada.
Leach
D H
DH