Cranial Nerves Flashcards
What does visceral efferent mean?
Parasympathetic, motor
Innervation of smooth muscle, cardiac muscle and glands
What does visceral afferent mean?
Sensory
Sensations from viscera including smell and taste
What does somatic efferent mean?
Innervation of skeletal muscles
Motor
What does somatic afferent mean?
Sensory
Sensations of vision, touch and pain, hearing and equilibrium
CN I name
Olfactory
CN function and category?
Sense of smell
VA
What happens with lesion to CN I?
Loss of smell (anosmia), ipsilateral
CN II name
Optic nerve
CN II function and category
Responsible for sight
VA
What happens with lesion to CN II?
Lose sight (anopsia, blindness), on the side of the lesion
CN III name and category
Oculomotor nerve, SE and VE
CN III functions and categories
SE: innervates extraocular muscles to move the eyeball, levator palpebrae superior to keep eyelid lifted
VE: innervates pupillary sphincter and ciliary muscles for pupil dilation and construction
CN III what happens with lesion
SE: Lateral strabismus (lateral downward gaze), ptosis (droopy eyelid)
VE: pupil dilates (mydriasis) and loss of pupillary light reflex
CN IV name and category
Trochlear nerve, SE
CN IV function
SE: innervates super oblique to rotate eye down and towards the middle
What happens with lesion to CN IV?
Eye rotates up and outward, diplopia (double vision)
CN V name and category
Trigeminal, SA and SE
What are the three branches of the trigeminal nerve (CN V)?
Ophthalmic, Maxillary, Mandibular
CN V functions, opthalmic branch
SA: sensory information (touch and pain) for forehead, eyes and nose
CN V lesion to ophthalmic branch leads to
Ipsilateral loss of touch and pain sensation to forehead
CN V functions, maxillary branch
SA: sensory information to midface (touch and pain)
CN V lesion to maxillary branch leads to
Ipsilateral loss of sensation of touch and pain for midface
CN V functions, mandibular branch
SA: sensation of touch and pain to the lower face, lower dental arch, anterior 2/3 of tongue (no taste), external auditory canal
SE: innervates muscles of chewing, tensor velli palatine (elevate palate), and anterior belly of digastric (upward and anterior movement of larynx)
CN V lesion to mandibular branch leads to
Jaw deviating to weak side
Ipsilateral loss of touch and pain sensation for lower face and touch sensation for anterior 2/3 of tongue
CN VI name and category
Abducens, SE
CN VI function
Innervates lateral rectus to pull eye up and laterally
CN VI lesion leads to
Eye deviating medially (medial strabismus)
CN VII name and categories
Facial, SE, SA, VE, VA
CN VII functions
SE: motor to all muscles of the face for facial expressions
SA: sensation to back of pinna
VE: innervates sublingual and submandibular salivary glands, nasal mucosa and lacrimal gland, stapedius muscle for acoustic reflex
VA: taste sensory info from anterior 2/3 of tongue
CN VII lesions lead to
Ipsilateral paralysis of the facial expression muscles
Ipsilateral loss of taste from anterior 2/3 of tongue (aguesia)
Stapedius paralysis causing acute hearing (hyperacusis)
CN VIII name and category
Vestibulocochlear
SA
CN VIII functions
Hearing and equilibrium
CN VIII lesion leads to
Ipsilateral deafness
Loss of equilibrium (balance issues, dizziness)
CN IX name and category
Glossopharyngeal
SA, SE, VA, VE
CN IX functions
SE: innervates stylopharyngeus to elevate and widen anterior portion of the pharynx, clear pharynx during swallowing
VE: innervates parotid salivary gland to produce saliva (breaks down food)
SA: sensation of tactile and pain from posterior 1/3 of tongue, soft palate (gag reflex)
VA: taste from posterior 1/3 of tongue
CN IX lesion leads to
Ipsilateral loss of taste from posterior 1/3 of tongue
Loss of gag reflex (sensory)
Dysphagia due to inability to sense bolus in back of mouth to trigger swallow
CN X name and category
Vagus, SE, VE, VA
CN X functions
SE: innervates pharyngeal constrictors and all palatal muscles except tensor veli palatine (CN V) to push down bolus and intrinsic muscles of larynx for voicing
SA: pharyngeal and laryngeal sensation for swallowing
VE: innervates heart and viscera to transverse colon
VA: sensory to viscera of transverse colon and heart
Lesion to CN X leads to
Uvula deviating contralaterally due to ipsilateral soft palate sagging
Loss of gag reflex (motor)
Unilateral vocal fold paralysis on ipsilateral side; weak and hoarse voice
Silent aspiration due to loss of sensation
CN XI name and category
Accessory nerve, SE
CN XI function
SE: innervates sternocleidomastoid and trapezius
CN XI lesion leads to
Difficulty shrugging ipsilateral shoulder
Difficulty turning head in contralateral direction
CN XII name and category
Hypoglossal nerve, SE
CN XII functions
SE: innervates all intrinsic tongue muscles (speech, swallowing), innervates all but one extrinsic tongue muscle (palatoglossus: CN X) for voicing
