THE COMMON DIGITAL ABTERY THE DIGITAL ARTERIES 659 



THE COMMON DIGITAL ARTERY 



The common digital artery (A. digitalis communis s. metacarpea volaris 

 superficialis)! is the direct continuation of the median. It descends in the 

 carpal canal along the medial side of the flexor tendons in company with the 

 medial volar nerve. Continuing down the limb it preserves this relation to the 

 tendons to the distal third of the metacarpus, where it inclines toward the middle 

 line of the limb behind the suspensory ligament, and divides into the medial and 

 lateral digital arteries. In the metacarpus the artery is related to the vein in front 

 and the nerve behind, and is covered by the fascia and skin. It furnishes collateral 

 branches to the suspensory ligament, the flexor tendons, and the skin. 



THE DIGITAL ARTERIES 



The digital arteries, medial and lateral (A. digitalis volaris propria medialis, 

 lateralis), are formed by the bifurcation of the common digital at the distal third 

 of the metacarpus. They diverge, pass down over the abaxial surface of the cor- 

 responding sesamoid at the fetlock, and descend parallel with the borders of the deep 

 flexor tendon to the volar grooves and foramina of the third phalanx. Entering the 

 latter the two arteries unite in the semilunar canal and form the terminal arch 

 (Arcus terminalis), from which numerous branches pass through the bone to the^ 

 dorsal surface and ramify in the corium of the wall and sole of the hoof .^ A num- 

 ber of branches emerge through the foramina at the distal border, where they anas- 

 tomose with each other in arciform fashion. 

 t 



These branches were named by Spooner the inferior communicating arteries, and the anas- 

 tomotic arch formed by them is termed the circumflex artery of the third phalanx (Chauveau) 

 or the artery of the distal border of the third phalanx (Leisering). 



Each artery is accompanied by a vein and by the digital nerves. Above the 

 fetlock the artery is most deeply placed and is covered by the vein; the nerve is 

 beh nd the vein. At the fetlock the artery has become superficial and is related 

 to the vein in front and the posterior branch of the nerve behind. The anterior 

 branch of the nerve crosses over the artery obliquely to the side of the first phalanx. 

 The artery and nerves are crossed obliquely by a small band, the tendon or ligament 

 of the ergot {vide digital fascia). 



In addition to branches to the joints, tendons and synovial sheath, ergot, and 

 skin, the digital arteries give off the following named branches: 



1. The artery of the first phalanx (A. phalangis primse)^ is a short trunk which 

 arises at a right angle about the middle of the first phalanx, and divides into 

 dorsal and volar branches. The dorsal branch (Ramus dorsalis) passes between 

 the first phalanx and the extensor tendon and ramifies on the* front of the digit, 

 anastomosing with its fellow. The volar branch (Ramus volaris) dips in between 

 the flexor tendons and the first phalanx and anastomoses with the opposite artery 

 between the superficial and middle distal sesamoidean ligaments. 



2. The artery of the digital cushion (A. toricaj phalangis tertiae) arises at the 

 proximal border of the cartilage of the third phalanx and passes backward and 

 downward to ramify in the digital cushion and the corium of the heels and frog. 



3. The dorsal artery of the second phalanx (Ramus dorsalis phalangis secundse) 

 arises a little above the level of the distal sesamoid bone, and passes forward under 

 cover of the cartilage of the third phalanx and the extensor tendon to the front of 

 the second phalanx, where it anastomoses with the opposite vessel. It gives 



1 This vessel is also termed the large or palmar metacarpal artery. 



2 The terminal part of the digital artery has been termed the plantar artery. 

 = Also termed the perpendicular artery. 



