Mechanoreceptors in the canine anterior cruciate ligaments.

Canine anterior cruciate ligaments were sectioned into sagittal, frontal and horizontal segments which were stained in bulk using a modified gold chloride method. Segments were then serially sectioned on a sliding microtome at 100 micron, mounted on slides, dehydrated and coverslipped. Abundant Ruffini and pacinian receptors were identified within the substance of the ligament. These receptors were innervated by 5 to 10 micron diameter axons penetrating from the peripheral synovium investing the ligament. The anterior cruciate ligament is capable of afferent input to the central nervous system of importance to the biomechanical function of the knee joint.