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.
The spinal accessory nerve, or cranial nerve XI (eleven), is a purely motor nerve which innervates the trapezius and sternocleidomastoid muscles.The sternocleidomastoid muscles are used to turn the head.here are 12 cranial nerves, they are as followed; (I) Olfactory (II) Optic (III) Oculomotor (IV) Trochlear (V) Trigeminal (VI) Abducens (VII) Facial (VIII) Vestibulocochlear â¦ (IX) Glossopharyngeal (X) Vagus (XI) Accessory (XII) Hypoglossal. 2 people found this useful. Valentin Popov. 21,056 Contributions.