Lab Unit 03: Cranial Nerves Flashcards
Sternocleidomastoid (SCM) – (Moore 991)
• Origin (PA):
Mastoid process
+ lateral half of superior nuchal line.
• Insertion (DA):
- Sternal head: Anterior surface of manubrium of sternum.
- Clavicular head: Superior surface of medial third of clavicle.
• Nerve:
- CN XI Accessory nerve (motor)
- AR C2, C3 (pain and proprioception).
• Action:
- Bilaterally: Flexes the neck.
- Unilaterally: Ipsilateral lateral neck flexion and contralateral rotation.
Upper Trapezius – (Moore 700)
• Origin (PA): Medial third of superior nuchal line \+ External occipital protuberance \+ Nuchal ligament \+ SP C7. • Insertion (DA): Lateral third of clavicle \+ Acromion. • Nerve: - CN XI Accessory nerve (motor) - AR C3, C4 (pain and proprioception). • Action: Elevates, adducts, and upwardly rotates scapula.
Middle Trapezius – (Moore 700)
• Origin (PA): SP T1-5. • Insertion (DA): Medial margin of acromion \+ superior lip of spine of scapula. • Nerve: - CN XI Accessory nerve (motor) - AR C3, C4 (pain and proprioception). • Action: Adducts the scapula.
Lower Trapezius – (Moore 700)
• Origin (PA): SP T6-T12.
• Insertion (DA): Spine of scapula.
• Nerve:
- CN XI Accessory nerve (motor)
- AR C3, C4 (pain and proprioception).
• Action: Depresses, adducts, and upwardly rotates scapula.
Cranial Nerves
• CN I Olfactory • CN II Optic • CN III Oculomotor • CN IV Trochlear • CN V Trigeminal - CN V1 Opthalmic division - CN V2 Maxillary division - CN V3 Mandibular division • CN VI Abducens • CN VII Facial • CN VIII Vestibulocochlear • CN IX Glossopharyngeal • CN X Vagus • CN XI Accessory • CN XII Hypoglossal
CN I Olfactory
• Special sensory visceral afferent
• Function: Smell
• Test:
- Unilateral test that must be performed bilaterally
- Block one nostril + place something pungent under the other nostril (coffee). Ask the patient when they smell it.
CN II Optic
• Special Sensory
• Function:
- Visual acuity
- Intactness of visual fields
• Test: w/ an Snellen chart placed 6m away
- close one eye and read the smallest line they can make out
- 1 miss is fine; 3-4 move up one line
CN III Olfactory
• Motor • Function: - Pupil constriction - Upward / Downward / Medial gaze - Eyelid elevation • Test: • Pupil constriction (direct & consensual) - Shine a light in patients eye. Look to see if the pupil of the eye the light is shone in constricts; also look if the contralateral pupil constricts. • Eyelid elevation - Look for symmetry of the eyelids - Ptosis (droopy eyelid)
CN IV Trochlear
- Motor
- Inferior with lateral eye movement (“cute shoes”)
- Test:
CN V Trigeminal
• Mixed • Function: • Sensory: - face, cornea, nasal & oral cavity, upper & lower teeth - Ophthalmic, Maxillary, Mandibular division • Motor: - Muscles of Mastication - Mandibular division
• Test:
• Sensory component:
- Sensation to face (hot/cold, sharp/dull)
- Corneal reflex:touch cornea w/ a paper towel
–> blinking
• Motor component:
- Palpate masseter muscles
CN VI Abducens
• Motor
• Function: Pure lateral eye movement
• Test: III, IV, VI tested together
- Smooth pursuits:
Check for smooth tracking (“follow my pen”)
- Saccades:
Accuracies (no jumping or overshooting; “look at my nose, look at my pen”)
CN VII Facial
• Mixed • Function: • Sensory: Taste to the anterior 2/3rds of tongue • Motor: Muscles of facial exression • Test: • Sensory component: - Taste test: ID sweet or salty • Motor component: - Corneal reflex:touch cornea w/ a paper towel --> blinking - "Make faces"
CN VIII Vestibulocochlear
• Sensory
• Function:
- Cochlear function: Hearing acuity
- Vestibular function: position in space related to position & movement of head and balance
• Test:
• Hearing tests:
- Rine Test (Air): tuning fork through air
- Weber Test (Bone): tuning fork on bony promnence: mastoid process, cranium
• Vestibular testing:
- cold/warm stimulus - -> SHOULD cause vertigo/nystagmus - -> direction of nystagmus or eye beating - -> COWS: cold opposite, warm same
• Vestibulo-ocular reflex
- Reflex test for III, VI & VIII - Eyes should stay on examiners nose while head thrust performed. - Conjugate horizontal gaze: coordinated eye movement
CN IX Glossopharyngeal
- Mixed
- Function:
- Sensory: touch & taste sensaton on posterior 1-3rd of tongue and pharyngeal wall (gag reflex)
- Motor: swolloing, gag reflex
• Test:
• Sensory component:
- Taste test: Does it taste bitter?
- Gag reflex: lightly stimulate back of throat
• Motor component:
- Have patient swallowing a liquid
CN X Vagus
• Mixed
• Function:
• Sensory: heart, lungs, trachea, pharynx, larynx, bronchi, GI tract, external ear
• Motor: heart, lungs, trachea, palate, pharynx, larynx, bronchi, GI tract
ex: constricts bronchioles, decreases HR, increases GI motility
• Test: • Say Ahhh - Test --> examine symmetry of uvula If lesion --> uvula deviates contralaterally (strong side is pulling) --> listen for hoarsness
- -> If both severed –> aphonia (unable to talk)
- -> if one severed –> deviates from affected side