The Morphology of the Hypoglossal Dorsal Root and its Ganglia in Holstein Cattle

This study was carried out to describe morphologically and morphometrically the hypoglossal dorsal root and its ganglia, using heads of 20 adult Holstein cattle of both sexes. The dorsal root of the hypoglossal nerve (XII) has always an evident dorsal root ganglion (DRG) including the accessory in 30% (6 of heads) or satellite ganglia in 10% (2 of heads). There were statistically significant differences between the lengths (right: 8.64+/-0.22 mm, left: 7.91+/-0.31 mm, p<0.01) of peripheral roots of the DRG in male. Statistical significance existed in the lengths (right: 7.01+/-0.43, left: 8.27+/-0.47, p<0.05) of the central roots of the DRG in male. Since the histological findings showed that each ganglion placed on the dorsal root of the XII had the general feature of a spinal ganglion, it can be said that the XII has the intracranial peripheral (sensory) fibers and carry directly sensory input to the brain stem. In conclusion, the present study is the first to reveal the morphology of the hypoglossal dorsal root with ganglia in Holstein cattle.