Neurology

Question 1

CN I

Answer 1

Sensory, no thalamic relay to cortex

1. Sensory: Smell

Question 2

CN II

Answer 2

Sensory

1. Sensory: Sight
2. Reflex: Sensory limb of light reflex with III

Question 3

CN III

Answer 3

Motor

1. Motor: Eye mvmt (SR, MR–most important, IR, IO–up and out)
2. PSNS: pupillary constriction (sphincter pupillae, E-W nucleus, mAchR); accomodation (ciliary muscle)
3. Reflex: Motor limb of light reflex with II

Question 4

CN IV

Answer 4

Motor

1. Motor: superior oblique–turns eye down and out/intorts eye (difficulty going down stairs)

Question 5

CN V1

Answer 5

Ophthalmic branch, sensory

1. Sensory: General sensation (touch, pain, temp) of forehead, scalp, cornea, dorsum of nose, nasal cavity
2. Reflex: sensory limb of blink/corneal reflex with VII

Question 6

CN V2

Answer 6

Maxillary branch, sensory

1. Sensory: General sensation of palate, nasal cavity, maxillary face, maxillary teeth

Question 7

CN V3

Answer 7

Mandibular, both

1. Sensory: General sensation of anterior 2/3 tongue, mandibular face, mandibular teeth
2. Motor: Muscles of mastication (temporalis, masseter, medial and lateral pterygoids, ant belly of gastric, mylohyoid, tensor tympani, tensor palati)

Jaw deviation towards lesions

Question 8

CN VI

Answer 8

Motor

1. Motor: lateral rectus–ABduction

Question 9

CN VII

Answer 9

Both

1. Motor: muscles of facial expression (orbicularis oculi and oris, platysma, buccinator), posterior digastric, stylohyoid, stapedius
2. PSNS: lacrimal and nasal/oral mucus glands (greater petrosal); submandibular and sublingual salivary glands (chroda tympani)–tears, mucus, saliva; can get dry and red eyes
3. Sensory: anterior 2/3 tongue (special afferent), pinna and external auditory canal (somatic afferent)
4. Reflex: Efferent/motor corneal blink with CN V1

Question 10

CN VIII

Answer 10

Sensory

1. Sensory: Hearing, linear acceleration (gravity), angular acceleration (head turning)

Question 11

CN IX

Answer 11

Both

1. Sensory: General sensation to oropharynx, carotid sinus and body, taste and general sensation to posterior 1/3 of tongue
2. Motor: Stylopharyngeus (the only muscle!)
3. PSNS: Saliva (parotid gland)
4. Reflex: Sensory/afferent limb of gag reflex with X