CRANIAL NERVES

Question 1

CN1: Olfactory

Answer 1

Sensory:
-Smell
Causes of anosmia:
- trauma
- Sinusitis, rhinitis
-Early stage Parkinson’s
-Alzheimer’s
Conditions that can affect CN1:
-Diabetes
-MS
-Tumors
-SLE

Question 2

CN2: Optic

Answer 2

Sensory: Vision
-Exits optic canal
-becomes optic chiasm (decussates)
Causes of visual disturbance:
1)Damage to L/R optic Nerve d/t ICP, ischemia, berry aneurysm.
2)Damage to optic chiasm causing bi temporal visual loss d/t pituitary gland tumor or hypertrophy.
3)Damage to optic tract d/t ischemia. Causes contra lateral vision loss=homonymous hemianopia(visual half)🚫🚫
4) Damage to lat. geniculate bodies d/t ischemia. Cause contra lateral vision loss=homonymous hemianopia(visual half)🚫🚫

Question 3

CN:3 Oculomotor

Answer 3

Motor: to all muscles of the eye except SO(CN4) and LR(CN6).
-Paralysis of nerve causes inability for the eye to move upward, downward and inward. Eye looks oblique/down and laterally only.
-Diplopia- double vision
-Ptosis of eyelid
-Pupil is dilated and non reactive to light.
-Accommodation is impossible

Question 4

CN:4 Trochlear

Answer 4

Motor: Superior Oblique
Damage: eye turn upwards and outward when looking at clinician.
-patient complains of diplopia

Question 5

CN:5 Trigeminal

Answer 5

Sensory: all of face except angle of the mandible which is innervated by cervical plexus.
-ophthalmic, maxillary,mandibular.

Motor: Muscles of mastication

Somatosensory: sensory to anterior 2/3rds

Clinical Correlation:
-Sensory loss in face
-Trigeminal neuralgia- Stabbing px
-Loss of corneal reflex(ophthalmic)
-Loss of masseter and temporalis muscle mass(mandibular)

Question 6

CN:6 Abducens

Answer 6

Motor: Lateral Rectus
Damage caused inability to turn the eye laterally.

Question 7

CN:7

Answer 7

Motor: muscles of facial expression, post. Diagastric, stylohyoid, Stapedius.

Sensory: sensation around EAM, taste to ant. 2/3 of tongue and soft palate

Parasympathetic to; submandibular gland, sublingual, lacrimal gland.

Branches:
Temporal
Zygomatic
Bucal
Mandibular
Cervical

Diseases that affect nerve:
-Bells palsy
-Herpes Zoster
-UMNL(stroke)

Question 8

CN:8 Vestibulocochlear

Answer 8

Sensory: Hearing
Damage: nystagmus and vertigo
Deafness and Tinnitus

Question 9

CN:9 Glossopharyngeal

Answer 9

Sensory:
-Taste from posterior 1/3 tongue
-pharynx
-palatine tonsils
-pharyngotympanic tube
-middle ear
-carotid sinus and body

Motor:
-styplopharyngeus muscle-swallowing

Damage:
-dysphagia

Question 10

CN10: Vagus

Answer 10

Sensory: pharynx, larynx, Thoracic and abdominal regions, epiglottis

Motor:
Intrinsic laryngeal muscles
Palatoglossal
Abdominal and thoracic viscera

Question 11

CN11: Accessory

Answer 11

Motor: SCM and Trapezius

Question 12

CN12: Hypoglossal

Answer 12

Motor:
Intrinsic muscles of the tongue
Styloglossus, hyloglossus, genioglossus