The innervation of the human meniscus.

Fourteen menisci from seven anatomic specimens were examined to identify their innervation. After staining by a modified gold chloride method, the menisci were sectioned on a sliding microtome and were studied under a light microscope. Free nerve endings in the peripheral and the medial thirds of the meniscal body were identified, and three types of encapsulated mechanoreceptors were found in the anterior and posterior horns. Based on these findings and a review of the relevant literature, it is considered that menisci both receive and transmit proprioceptive information. Therefore, they not only are stabilizers of this joint, but also contribute to the function of deep sensitivity.

Mechanoreceptors in the posterior cruciate ligament. Histologic study on cadaver knees.

The purpose of the study was to identify mechano-receptors in the healthy, human posterior cruciate ligament. Ten ligaments from 10 fresh cadavers were studied with light microscopy. In addition to free nerve endings, two types of encapsulated mechanoreceptors were identified. They were located at the femoral and tibial attachments, and on the surface of the ligament. These findings support the hypothesis that the posterior cruciate ligament has an anatomic basis for a discriminating afferent flow of nerve impulses to the central nervous system. Therefore, its neural network may play a role in regulating the contraction of muscle groups that are fundamental to knee stability.