Microvasculature of the tibialis anterior tendon.

Subcutaneous rupture of the tibialis anterior tendon is an uncommon condition for which the etiology is unclear. The existence of a hypovascular zone has been proposed as an etiology for rupture of the tibialis anterior tendon. To investigate this possibility, the microvascular anatomy of the tibialis anterior tendon was studied using a modified Spalteholz technique. The vascular supply to the tibialis anterior tendon arises from proximal and distal ventral vinculae. Muscular branches of the anterior tibial artery, proximally, and the medial tarsal arteries, distally, form an intratendinous, longitudinal, competent blood supply. The tendon also receives a rich vascular blood supply from the synovial sheath. The blood supply appears adequate throughout the course of the tibialis anterior tendon, and no hypovascular region was noted at the common site of rupture 1 to 3 cm proximal to its insertion. No relationship was noted between increasing age and alteration in blood supply.