Distribution and Structure of Mechanoreceptors in the Mandibular Joint of STR/IN-Mice

Summary

The structure and innervation of the mandibular joint were investigated in the STR/IN-mice by light and electron microscopy. In the mouse the mandibular joint consists of the fossa mandibularis, the condylus mandibulae, and an articular disk which completely separates both articular surfaces. The joint capsule is flaccid and comprises a synovial layer and a membrana fibrosa that is usually very thin. Two types of nerve endings were observed: 1. free nerve endings inside the joint capsule ventromedial and dorsolateral in the membrana fibrosa (myelinated afferent axons of 1–2 μm in diameter) and 2. Ruffini corpuscles at the insertion of the lateral pterygoid muscle at the articular disk and the collum mandibulae (axon diameter 3–5 μm). A Pacinian corpuscle was not observed in eight joint capsules studied.