The Anterior Cruciate Ligament

The anterior cruciate ligament (ACL) is a central stabilizer of the knee that prevents anterior motion in both full extension and 90 degrees of flexion. It is embryologically present by 6 weeks of gestation [5]. Its blood supply is from the middle geniculate. Scapinelli confirmed this with his autopsy dissections and contrast injections. There is minimal supply from the bone origin or insertion [33]. Schutte et al. identified mechanoreceptors and free nerve endings that account for motion, speed, acceleration, and pain reception. The innervations account for proprioception [36]. The double bundle structure enables the ligament to stabilize the knee throughout the range of motion [92].