Cranial Nerves Flashcards
What are the features of the Olfactory nerve (1)?
Type: sensory
Foramen: cribriform plate
Function: Smells
Lesion: Anosmia
What are the features of Optic nerve (2)?
Type: sensory
Foramen: optic canal
Function: sees
Lesion:
- Anopsia
- Loss of light reflex with III
- Only nerve to be affected by MS
What are the features of Oculomotor nerve (3)?
Type: motor
Foramen: SOF
Function:
- Innervates SR, IR, MR, IO extraocular muscles: adduction (MR) most important action
- Raises eyelid (levator palpebrae superioris)
- Constricts pupil (sphincter pupillae)
- Accommodates (ciliary muscle)
Lesion:
- Diplopia, external strabismus
- Loss of parallel gaze
- Ptosis
- Dilated pupil, loss of light reflex with II
- Loss of near response
What are the features of Trochlear nerve (4)?
Type: Motor
Foramen: SOF
Function:
- Superior oblique—depresses and abducts eyeball (makes eyeball look down and out)
- Intorts
Lesion:
- Weakness looking down with an adducted eye
- Trouble going down stairs
- Head tilts away from lesioned side
What are the features of Trigeminal nerve (5)?
Type: Mixed
Foramen: V1 - SOF, V2 - f. rotundum, V3 - f. ovale
Function:
- General sensation (touch, pain, temperature) of forehead/scalp/cornea
- General sensation of palate, nasal cavity, maxillary face, maxillary teeth
- General sensation of anterior two-thirds of the tongue, mandibular face, mandibular teeth
- Motor to muscles of mastication (temporalis, masseter, medial and lateral pterygoids) and anterior belly of digastric, mylohyoid, tensor tympani, tensor palati
Lesion:
- V1—loss of general sensation in the skin of forehead/scalp. Loss of blink reflex with VII
- V2—loss of general sensation in the skin over maxilla, maxillary teeth
- V3—loss of general sensation in the skin over mandible, mandibular teeth, tongue, weakness in chewing. Jaw deviation toward the weak side.
Trigeminal neuralgia—intractable pain
in V2 or V3 territory
What are the features of Abducens nerve (6)?
Type: motor
Foramen: SOF
Function: Lateral rectus—abducts eyeball
Lesion:
- Diplopia, internal strabismus
- Loss of parallel gaze, “pseudoptosis”
What are the features of Facial nerve (7)?
Type: mixed
Foramen: Internal auditory meatus
Function:
- To muscles of facial expression, posterior belly of digastric, stylohyoid, stapedius
- Salivation (submandibular, sublingual glands)
- Skin behind ear
- Taste in anterior 2/3 of tongue/palate
- Tears (lacrimal gland)
Lesion:
- Corner of mouth droops, cannot close eye, cannot wrinkle forehead, loss of blink reflex, hyperacusis; Bell palsy— a lesion of nerve in the facial canal
- Pain behind ear
- Alteration or loss of taste (ageusia)
- Eye dry and red
What are the features of the Vestibulocochlear nerve (8)?
Type: sensory
Foramen: Internal auditory meatus
Function:
- Hearing
- Angular acceleration (head turning)
- Linear acceleration (gravity)
Lesion:
- Sensorineural hearing loss
- Loss of balance, nystagmus
What are the features of the Glossopharyngeal nerve (9)?
Type: mixed
Foramen: jugular
Function:
- Oropharynx sensation, carotid sinus/ body
- Salivation (parotid gland)
- All sensation of posterior one-third of the tongue
- Motor to one muscle — stylopharyngeus
Lesion: Loss of gag reflex with X
What are the features of the Vagus nerve (10)?
Type: mixed
Foramen: jugular
Function:
- To muscles of palate and pharynx for swallowing except tensor palati (V) and stylopharyngeus (IX)
- To all muscles of larynx (phonates)
- Sensory of larynx and laryngopharynx
- Sensory of GI tract
- To GI tract smooth muscle and glands in foregut and midgut
Lesion:
- Nasal speech, nasal regurgitation
- Dysphagia, palate droop
- Uvula pointing away from the affected side
- Hoarseness/fixed vocal cord
- Loss of gag reflex with IX
- Loss of cough reflex
What are the features of the Accessory nerve (11)?
Type: motor
Foramen: magnum, jugular
Function:
- Head rotation to opposite side (sternocleidomastoid)
- Elevates and rotates scapula (trapezius)
Lesion:
- Weakness turning chin to opposite side
- Shoulder droop
What are the features of the Hypoglossal nerve (12)?
Type: motor
Foramen: hypoglossal canal
Function: Tongue movement (styloglossus, hyoglossus, genioglossus, and intrinsic tongue muscles palatoglossus is by X)
Lesion: Tongue pointing toward the same (affected)
side on protrusion (lick the lesion)
