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.
Accessory nerve. (Redirected from Accessory nerves) The accessory nerve is a cranial nerve that supplies the sternocleidomastoid and trapezius muscles. It is considered the eleventh of twelve pairs of cranial nerves, or simply cranial nerve XI, as part of it was formerly believed to originate in the brain.