Definition of COUNTERBORE. : to form a counterbore in: enlarge (part of a hole) by means of a counterbore.ADVERTISEMENT.efinition of COUNTERBORE. 1. : a flat-bottomed enlargement of the mouth of a cylindrical bore. 2. : a drill for making a counterbore â compare countersink.
The vestibulocochlear nerve (auditory vestibular nerve) , known as the eighth cranial nerve, transmits sound and equilibrium (balance) information from the inner ear to the brain.
1 Olfactory nerve is the only sensory cranial nerve that projects directly to the cerebral cortex. 2  Optic nerve terminates in thalamus. 3  Vagus nerve is the only cranial nerve which supplies in areas other than head and neck. 4  Trochlear nerve is the only cranial nerve to emerge from dorsal surface of brain stem.nteresting facts regarding cranial nerves. 1  Olfactory nerve is the only sensory cranial nerve that projects directly to the cerebral cortex. 2  Optic nerve terminates in thalamus.