Mechanoreceptors in the posterior cruciate and lateral collateral ligaments of the human Knee and the lateral collateral ligament of the canine knee

Examinatìon of human posterior cruciate (PCI) and lateral collateral (LCL) ligaments and thè canine LCL by means ofRuffmi's gola chlo- ride method revealed thè presence ofboth common nervefibres and Golgi-Mazzoni and Ruffìni corpuscles. The Ruffìni corpuscles were always isolated in thè human knee. In thè canine LCL, there were bundles ofnerve fibres ending in groups of Ruffìni corpuscles interspersed with isolated Golgi-Mazzoni corpuscles, as well as a poikilo- morphous fibre expanding into a Pacini corpuscle and three Ruffìni corpuscles. Some Ruffìni corpuscles in these ligaments resembled thè Golgi tendon organ. Mechanoreceptors were much more numerous at thè ends than in thè middle ofthe ligaments. They were present in both thè subsynovial and thè interfascicular connective tissue, and surrounded by vessel networks. It would seem that thè numerica! ratìo between Ruffìni and Golgi-Mazzoni corpuscles is related to thè type of stress (tension or torsion) to which a ligament is subjected. These fmdings are in line with previously reported personal observations in thè human mediai collateral ligament (MCLJ.