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.
Functions. Each of the 12 cranial nerves has a specific function that helps the brain control the actions of the body. 1  The olfactory nerve is involved in the sense of smell. 2  This nerve has access to the cerebral cortex, but does not pass through the thalamus like other cranial nerves. The olfactory nerve is involved in the sense of smell. 2  This nerve has access to the cerebral cortex, but does not pass through the thalamus like other cranial nerves. 3  The optic nerve is involved in the sense of sight. 4  Responsible for vision, damage to this nerve can result in temporary or permanent blindness.