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.
4. Trochlear. This motor nerve also supplies to the midbrain and performs the function of handling the eye muscles and turning the eye. 5. Trigeminal. This is a type of largest cranial nerve in all and performs many sensory functions related to nose, eyes, tongue and teeth.here are total 12 pairs of cranial nerves that originate from our brain and brain stem. Each of them carries different functions related to different senses of body. Apart from sensory functions there are also some that work as motor nerves or mixed nerves. Here is a brief description of 12 cranial nerves.