The sensory innervation of the medial ligament of the knee joint

Proprioception at the knee joint is not easy to explain on account of the difficulty in estimating the influence of muscular contraction on the inflow of sensory nerve impulses from endings located in the joint. The tension in the muscles is certainly disturbed by the anaesthetic necessarily employed during experimental work and, apart from passive movements produced by externally applied forces, the production of normal joint movements is difficult. To avoid these difficulties, this work began with a search for a part of the knee joint unconnected to skeletal muscle which might be a source of proprioceptive information. Two sites seemed promising, the collateral ligaments and the cruciate ligaments. The medial ligament was chosen for the first trial because it is readily accessible and, as is well known, it is subjected to tension which increases during joint extension. Some initial experiments on the medial ligament have already been described (Andrew & Dodt, 1953).