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 Cranial Nerves Cranial Nerves  Twelve pairs of cranial nerves arise from the brain  They have sensory, motor, or both sensory and motor functions  Each nerve is identified by a number (I through XII) and a name  Four cranial nerves carry parasympathetic fibers that serve muscles and glands. Cranial Nerves Cranial Nerves  Twelve pairs of cranial nerves arise from the brain  They have sensory, motor, or both sensory and motor functions  Each nerve is identified by a number (I through XII) and a name  Four cranial nerves carry parasympathetic fibers that serve muscles and glands.