Morphological study on the rootlets comprising the root of the intermediate nerve.

The number and arising sites of the rootlet comprising the intermediate nerve root were investigated in 100 sides of human brains. The arising sites of the rootlets were the pons halfway between the facial and vestibulocochlear nerves (31.9%), the arising portion of the vestibulocochlear nerve on the pons (28.8%) and the stem of the vestibulocochlear nerve (15.9%). The number of roots varied from one to five, with the most common being one root (58%). The number of rootlets per root also varied from one to five. Most of the roots had one rootlet (63%), while 2% of the roots had five rootlets. The variation of the arising sites of the intermediate nerve rootlets and its clinical significance were also discussed.