‘Mice’ in the joint

Synovial chondromatosis of the temporomandibular joint (TMJ) is rare, and is characterised by the presence of loose bodies (joint mice). It can be confused clinically with myofascial pain dysfunction syndrome, and histologically with chondrosarcoma. Diagnosis involves clinical, radiographic, and histological examination. Arthroscopy is a useful, minimally-invasive adjunctive diagnostic investigation.