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.
Cranial Nerve. Number and Name. Function(s) of Cranial Nerve; 1. I olfactory (sensory) Smell. 2. II optic (sensory) Vision, also called eyesight. (Each optic nerve contains approx. a million nerve fibres that receive information from the rod and cone cells of the retina.) 3. III oculomotor (mixed, mainly motor)