Neuroanatomy, Trigeminal Reflexes

Excerpt

As the largest of the cranial nerves, the trigeminal nerve is responsible for the primary sensory input from the head and neck as well as providing motor innervation to the muscles of mastication. The trigeminal nerve innervates key vascular structures such as the brainstem, the cavernous sinus, and peripheral divisions. With such an extensive distribution within the head and neck, various lesions may contribute to trigeminal neuralgia or dysfunction. The goal of this activity is to review the neuroanatomy of the trigeminal nerve and cover the reflex tests employed to distinguish between lesions of the trigeminal nerve.

The trigeminal nerve is the fifth cranial nerve (CN V) and the largest of the paired cranial nerves. It is a mixed nerve that partially innervates the craniofacial region along with the facial nerve. The fifth cranial nerve contains three terminal branches that innervate the skin of the face and neck, mucous membranes and paranasal sinuses of the face, the corneas, and the muscles of mastication. A trigeminal nerve reflex is a natural response to stimuli indicating the proper functioning of the nerve. Each area innervated by the trigeminal nerve can undergo assessment through the presence and strength of a trigeminal nerve reflex.