Vascular anatomy of flexor tendons. I. Vincular system and blood supply of the profundus tendon in the digital sheath.

The detailed blood supply of the flexor tendons in the digital canal was studied in 35 fresh human hands by means of an India ink-latex vascular injection technique. The specimens were examined by first exposing the pulley system, followed by examination of the intact tendon which had been rendered transparent by immersion in a solution of tributyl and tricresyl phosphate. Five annular and three cruciform pulleys were shown. There were five types of long vincula to the profundus (VLP) and three types of long vincula to the superficialis (VLS). The vincular systems of index and little fingers were symmetrical. Occasionally, neither the VLP nor the VLS was found in either the long or the ring fingers. The vincula received blood supply from four transverse branches of the digital arteries. A volar avascular area of the profundus tendon was seen in the cleared cross-sections, and the cross-over zone of its intrinsic vessels was found to be at the midproximal phalanx.