Cranial Nerves

Consultants in Dysphagia Evaluation and Management

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Speech Pathologist Reference Sheet
By. Ronda Polansky M.S. CCC-SLP
THE NERVE OF IT ALL!
CRANIAL NERVE REFERENCE SHEET

        The cranial nerves innervate the muscles of the jaw, face, tongue, neck, pharynx, and larynx. Some of them are motor, some are sensory and some are mixed nerves, containing both sensory and motor fibers. Six of them are involved in speech and swallowing, and are therefore very important to the speech, language pathologist.
The Six Cranial Nerves Involved in Speech and Swallowing  
CN V – – the trigeminal nerve
CN VII – – the facial nerve
CN IX – – the glossopharyngeal nerve
CN X – – the vagus nerve
CN XI – – the spinal accessory nerve
CN XII – – the hypoglossal nerve
 

CN V is the trigeminal nerve.
It provides motor innervation to the muscles that control the mandible (jaw), the tensor veli palatini muscle of the velum, and the tensor tympani muscle of the middle ear. It mediates sensation from the head, jaw, face, some of the sinuses and tactile sensation from the anterior two thirds of the tongue.
 

CN VII or the facial nerve
 Its motor nucleus which is located in the junction of the pons and medulla innervates all of the muscles of facial expression including those in the forehead, cheeks, and lips, as well as the stapedius muscle of the middle ear. It also sends motor impulses to the rest of the ear; if you can wiggle your ears; this action is mediated by CN VII. The facial nerve mediates taste in the anterior two thirds of the tongue.
 

CN IX, or the glossopharyngeal nerve, is a mixed nerve.
Its motor aspect contributes to the action of the middle pharyngeal constrictor muscle and innervates the stylopharyngeus muscle.  Its sensory aspect carries input from the posterior one third of the tongue, the velum, and the pharynx including the tonsils. The glossopharyngeal nerve is responsible for taste in the posterior one third of the tongue and for tactile sensation to the posterior part of the oral cavity, including the velum, tonsils, and walls of the oropharynx. It provides the feedback that is most important in the elicitation of the swallow.
Feedback from motor movements, especially tongue movements which are mediated by the hypoglossal nerve, also help to trigger the swallow. Input from both the cerebral cortex and the cerebellum is responsible for the coordination and timing of the motor movements involved in swallowing
 

CN X is the vagus nerve. This mixed nerve originates in the medulla.
One of the motor nuclei of the vagus innervates the majority of the viscera, including the heart, respiratory system, and digestive system. Another motor nucleus sends motor commands to the pharyngeal constrictor muscles and completely controls the intrinsic musculature of the larynx. The superior branch of the vagus innervates the cricothyroid muscle and so is involved in pitch changes. Its recurrent branch innervates all of the other intrinsic laryngeal musculature.  The vagus also innervates the glossopalatine and levator veli palatine muscles, making it primarily responsible for palatal functioning.
 

CN XI is the spinal accessory nerve,
A motor nerve that originates in the medulla. It innervates the trapezius and sternocleidomastoid muscles of the neck. It also sends some motor messages to the uvula and the levator veli palatine (raises the velum).
 

CN XII, is the hypoglossal nerve,
 Another motor nerve that originates in the medulla. It controls tongue movement, innervating both the intrinsic and extrinsic tongue muscles.
Mnemonic for the Cranial Nerves

The facial nerve could also be classified as both sensory (taste for anterior two thirds of tongue) and motor, in which case the word in this part of the rhyme would change to “brother.” It is usually classified as a motor nerve.  CSU, Chico, Patrick McCaffrey, Ph.D.