Function:
Cranial nerve VII has four components; pain and temperature from the "EAR", taste from the anterior two-thirds of the tongue, motor innervation of the muscles of facial expression and autonomic innervation of the submandibular, sublingual and lacrimal glands.

Pathway:
Cells of origin of the "EAR" fibers lie in the geniculate ganglion; fibers end in caudal spinal nucleus V. Cells of origin of taste fibers lie in the geniculate ganglion; fibers end in rostral nucleus solitarius. Branchiomotor fibers to muscles of facial expression lie in the motor VII nucleus. Preganglionic parasympathetic fibers arise from superior salivatory nucleus (lies medial to motor VII in the pontine tegmentum).

Deficits:
Lesion of C.N. VII at the stylomastoid foramen involves only branchiomotor fibers to muscles of facial expression. Lesion more central, just distal to the geniculate ganglion in the facial canal, interrupts the branchiomotor fibers AND the incoming taste fibers, the outgoing preganglionic fibers to the submandibular ganglion and the branchiomotor fibers to the stapedius muscle (hyperacusis). Lesion even more centrally in the internal auditory meatus results in all of the deficits already mentioned AND the loss of tearing.

Other Note:
ALL DEFICITS ARE IPSILATERAL TO THE LESION!