Cranial Nerves VIII-XII: Functions and Components

name, components, functions, and clinical importance of CN IX?

name: glossopharyngeal

functions/components:

• SpS → SVA: taste in posterior 1/3 of tongue

• brachial motor (GSE): motor control of stylopharyngeus muscle

• brachial sensory (GSA): sensation in inner surface of eardrum, skin of part of pinna, upper pharynx

• visceral sensory (GVA): sensation to carotid bodies (chemoreceptors that monitor oxygen, breathing, HR)

• visceral motor (GVE): motor control over parotid glands (salivary glands)

clinical importance: swallowing, gag reflex, taste, saliva secretion

name, components, functions, and clinical importance of CN X?

name: vagus → “wandering”

functions/components:

• SpS → SVA: taste in back of pharynx

• brachial motor (GSE): voluntary control over pharynx, palate, larynx

• visceral motor (GVE): involuntary control of organs below the head at the terminal ganglia (heart, lungs, gut)

• visceral sensory (GVA): sensation from thoracic and abdominal viscera (heart, lungs, gut) and pharynx

clinical importance: control over laryngeal, pharyngeal, and esophageal muscles

notes: longest and largest cranial nerve

name, components, functions, and clinical importance of CN XI?

name: spinal accessory

functions/components:

• brachial motor (GSE): voluntary control over trapezius and sternocleidomastoid muscles

notes: originates in spinal cord, travels up through foramen magnum and then back down through jugular foramen

clincal importance: posture while eating and swallowing

name, components, functions, and clinical importance of CN XII?

name: hypoglossal

functions/components:

• brachial motor (GSE): voluntary control of intrinsic and extrinsic tongue muscles

clinical importance: swallowing, chewing, manipulating food