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 The abducens nerve allows the eyes to move away from the midline of the face. 2  This nerve must work with cranial nerves III and IV for correct vision. 3  If these nerves donât work together, double vision occurs. 4  The facial nerve controls the muscles used in smiling, frowning, and other facial expressions.he 12 cranial nerves control some of the most important functions of the body. In addition, these nerves allow us to feel pain, indicating when there is a serious problem that requires medical intervention.