Anatomy of Hereditary Bovine Syndactylism. III. Angiology

Abstract

Angiologic anomalies of the limbs of six syndactylous Holsteins were essentially adaptations to the single-toed condition. In the metacarpal area, the parent arteries were like the normal. The dorsal metacarpal artery ended at the fetlock; in extreme cases, the distal perforating metacarpal artery was absent. A lateral and a medial volar digital artery supplied the single digit, originating either from the reunited trunk of the ulnar and radial artery, or from the ulnar. The rundimentary volar digital artery arose from either the medial, lateral, or both, volar digital arteries. The latter supplied the dewclaws and the dorsal area of the digit with smaller branches, had two volar anastomoses, and terminated in an anastomosing arch in the third phalanx. Veins general followed the arteries. The lateral radicle of the dorsal metacarpal vein anastomosed with the distal volar venous arch. The proximal part of the lateral volar digital vein was remotely dorsal to the lateral volar digital artery.The arteries above the distal plantar arch were normal. Arising from the distal plantar arch were a lateral and a medial plantar digital artery and a small axial artery. The two plantar digital arteries branched and terminated as the corresponding arteries of thoracic limbs. The well-developed dorsal metatarsal artery continued as a small axial branch to the fetlock. A well-developed distal perforating metatarsal artery was present. The veins followed the arterial pattern. The dorsal metatarsal vein joined the saphenous vein instead of the recurrent tarsal.