Cranial Nerves Mnemonics : : Anatomy, Functions, and Clinical Insights by Medical Learner

Cranial Nerves : Flashcard By Medical Learner.

Cranial nerves are 12 pairs of nerves that emerge from the brain and brainstem, controlling sensory, motor, and autonomic functions of the head, neck, and beyond. In this article, we'll delve into the anatomy, functions, and clinical correlations of each cranial nerve.

Mnemonic for Cranial Nerves :

"Oh, Oh, Oh, To Touch And Feel Very Green Vegetables, AH!"

Or

"Ooh, ooh, ooh to touch and feel very good velvet. Such heaven "

1. Olfactory (I)

2. Optic (II)

3. Oculomotor (III)

4. Trochlear (IV)

5. Trigeminal (V)

6. Abducens (VI)

7. Facial (VII)

8. Vestibulocochlear (VIII)

9. Glossopharyngeal (IX)

10. Vagus (X)

11. Accessory (XI)

12. Hypoglossal (XII)

Mnemonic for Functions of Cranial Nerves (Sensory/Motor/Both):

"Some Say Money Matters , But My Brother Says Big Brains Matter More."

Detailed Functions and Clinical Correlations

1. Olfactory (CN I) - Sensory

Function: Smell

Lesion: Anosmia (loss of smell)

Clinical Test: Smell test with familiar odors

2. Optic (CN II) - Sensory

Function: Vision

Lesion: Visual field defects (hemianopia)

Clinical Test: Visual acuity, visual fields

3. Oculomotor (CN III) - Motor

Function: Eye movement, pupil constriction (parasympathetic)

Lesion: Ptosis, diplopia, "down and out" eye, dilated pupil

Clinical Test: Pupil reaction, extraocular movements

4. Trochlear (CN IV) - Motor

Function: Eye movement (superior oblique muscle)

Lesion: Vertical diplopia, head tilt

Clinical Test: Downward eye movement

5. Trigeminal (CN V) - Both

Function: Facial sensation, mastication muscles

Lesion: Facial numbness, jaw weakness, trigeminal neuralgia

Clinical Test: Sensory testing, jaw clenching

6. Abducens (CN VI) - Motor

Function: Eye abduction (lateral rectus muscle)

Lesion: Diplopia, medial strabismus

Clinical Test: Lateral eye movement

7. Facial (CN VII) - Both

Function: Facial expression, taste (anterior 2/3 of the tongue), lacrimation, salivation

Lesion: Bell's palsy (LMN lesion), forehead sparing in stroke (UMN lesion)

Clinical Test: Facial movements, taste test

8. Vestibulocochlear (CN VIII) - Sensory

Function: Hearing and balance

Lesion: Hearing loss, vertigo, tinnitus

Clinical Test: Rinne and Weber tests, balance assessment

9. Glossopharyngeal (CN IX) - Both

Function: Taste (posterior 1/3), swallowing, salivation (parotid), carotid body reflexes

Lesion: Loss of gag reflex, impaired swallowing

Clinical Test: Gag reflex, taste test

10. Vagus (CN X) - Both

Function: Autonomic control of heart, lungs, digestion, swallowing, phonation

Lesion: Hoarseness, dysphagia, uvula deviation (away from lesion)

Clinical Test: Voice quality, palate elevation

11. Accessory (CN XI) - Motor

Function: Shoulder shrug (trapezius), head rotation (sternocleidomastoid)

Lesion: Weak shoulder shrug, head turn weakness

Clinical Test: Shoulder shrug, head rotation against resistance

12. Hypoglossal (CN XII) - Motor

Function: Tongue movement

Lesion: Tongue deviation toward the lesion side (LMN)

Clinical Test: Stick out tongue

Clinical Correlations

1. Bell's Palsy (CN VII) is a sudden facial paralysis.

2. Trigeminal Neuralgia (CN V) is a sharp facial pain.

3. Diplopia (CN III, IV, VI) is double vision due to extraocular muscle weakness.

4. Horner's Syndrome is ptosis, miosis, anhidrosis due to sympathetic disruption (affecting CN III).