Vascular anatomy of the ovine anterior cruciate ligament. A macroscopic, histological and radiographic study.

Sheep are being extensively utilized in animal models for orthopaedic research, but the vascular anatomy of their anterior cruciate ligament (ACL) has not yet been thoroughly described. This study demonstrates the blood supply to the ACL. Vascular injection with plastogen G, lead oxide and India ink was performed in 12 back limbs of Styrian mountain sheep, and gross observations, microradiography and routine histology were done. The large vessel and the microvascular anatomy are similar to those described for humans. The middle genicular artery and the descending genicular artery contribute vessels that supply the ACL. Epiligamentous vascular plexuses give off capillaries which penetrate the ligament substance and supply numerous, longitudinally oriented intraligamentous vessels. These findings make the Styrian mountain sheep a potential animal model for biologic investigations of ACL pathology.