Vascularisation of the geniculate ganglion.

Abstract

Lack of the relevant data in the literature and possible clinical significance of the geniculate ganglion vasculature inspired us to examine the vessels of this ganglion. Twelve temporal bones were taken during autopsy and microdissected. Four geniculate ganglions were taken as well, serially sectioned and used for haematoxylin-eosin and trichrome staining, and for CD34 immunostaining. The geniculate ganglion was supplied by the petrosal artery, which averaged 1.1 in number, 0.44 mm in the outer diameter, 0.24 mm in the luminal diameter, and 17.1 mm in length. The artery approached the greater petrosal nerve, giving off 1-3 twigs to it with a mean diameter of 24 μm, and entered the nerve hiatus or a small bone opening close to the ganglion. Before the artery continued to the tympanic segment of the facial nerve, it gave rise to 1 (8.33%), 2 (75.00%) or 3 (16.67%) branches to the geniculate ganglion, which ranged in diameter between 18 μm and 56 μm (mean 29 μm). From the formed superficial network, several twigs penetrated the ganglion and built an intraganglionic plexus. The counting, performed in microscopic fields, each measuring 341.7 μm × 250.0 μm in size, contained between 20 and 38 (mean 28.1) ganglion cells, as well as from 87 to 143 microvessels (mean 99.8), so that the neuron/vessel ratio was 1:3.6. This is the first detailed examination of the geniculate ganglion vasculature. The obtained data could be of clinical importance, especially in relation to the Bell's palsy, ganglionitis, geniculate neuralgia, petrous bone imaging, and operations in the same region.