Origin of sympathetic and sensory innervation of the temporo-mandibular joint. A retrograde axonal tracing study in the rat.

The cells of origin of sensory and sympathetic innervation of the temporo-mandibular joint were studied by the intraaxonal transport method. Horseradish peroxidase or lectin-conjugated horseradish peroxidase was injected into the temporo-mandibular joint unilaterally in adult rats. Labelled cells were observed ipsilaterally in the superior cervical and stellate sympathetic ganglia, in the sensory trigeminal ganglion and in the second to fifth dorsal root ganglia; none were found contralaterally. The results are discussed in relation to the hypothesis that a nervous mechanism might be involved in the pathogenesis of joint inflammation.