Eur J Anat, 3 (1): 1-5 (1999)

An investigation of dual innervation of the temporomandibular joint and external ear canal of the rat

Brodie C., Folan-Curran J.

Department of Anatomy, National University of Ireland, Galway, Ireland

ABSTRACT Patients suffering from temporomandibular joint disease may experience referred otalgia, or pain localised to the ear. The aim of this study was to determine if afferent fibers from the temporomandibular joint and the external acoustic meatus of the rat converge to a single afferent perikaryon in the semilunar ganglion of the trigeminal nerve. In anaesthesised animals Fluorogold was rejected into either the temporomandibular joint cavity or the external ear canal and True Blue was administered to the other location in Sprague Dawley rats. Ten to fourteen days later the animals were anaesthesised and the trigeminal ganglia removed for cryostat sectioning and fluorescence microscopy. A small proportion of nerve fibers supplying the temporomandibular joint and the external ear canal converge to single perikarya within the semilunar ganglion of the trigeminal nerve of the rat. This does not occur in a sufficiently high degree to account for the phenonomen of referred otalgia caused by a primary pathology in the temporomandibular joint.

Keywords: fluorogold, true blue, animal experiment, animal tissue, article, external auditory canal, innervation, nonhuman, otalgia, perikaryon, rat, sensory nerve, temporomandibular joint, temporomandibular joint disorder, trigeminal nerve, trigeminus ganglion