Functions of the Cranial Nerves

Introduction

• Purpose: Basic review on the functions of the cranial nerves.
• Visual Aid: Uses a facial outline drawing to help memorize the functions (numbers representing different nerves).

Drawing Guide

• Outline of Face: Two 7s (one forward, one backward).
• Nose: Number 1.
• Eyes: Large 2s.
• Eyebrows: 3s.
• Medial Corners of Eyes: Small 4s.
• Mouth and Forehead: Large 5.
• Sides of Eyes: 6s.
• Ears: 8s.
• Tongue and Tongue Ring: 9, 10, 12.
• Shoulders: 11.

Cranial Nerves and Their Functions

Cranial Nerve 1: Olfactory Nerve

• Type: Sensory
• Function: Sense of smell.
• Location in Drawing: Nose.

Cranial Nerve 2: Optic Nerve

• Type: Sensory
• Function: Sense of sight or vision.
• Location in Drawing: Eyes.

Cranial Nerve 3: Oculomotor Nerve

• Type: Motor
• Functions:
  • Eye movement.
  • Eyelid opening.
  • Pupillary constriction.
  • Lens accommodation (focusing at different distances).

Cranial Nerve 4: Trochlear Nerve

• Type: Motor
• Function: Eye movement.

Cranial Nerve 5: Trigeminal Nerve

• Type: Sensory & Motor
• Functions:
  • Facial sensation (pain, soft touch).
  • Sensory component includes anterior two-thirds of the tongue.
  • Motor component: Muscles of mastication (jaw movement, chewing).

Cranial Nerve 6: Abducens Nerve

• Type: Motor
• Function: Eye movement.

Cranial Nerve 7: Facial Nerve

• Type: Sensory & Motor
• Functions:
  • Motor: Facial expressions (smiling, frowning).
  • Sensory: Taste on the anterior two-thirds of the tongue.

Cranial Nerve 8: Vestibulocochlear Nerve

• Type: Sensory
• Functions:
  • Hearing.
  • Balance.
• Location in Drawing: Ears.

Cranial Nerve 9: Glossopharyngeal Nerve

• Type: Sensory & Motor
• Functions:
  • Sensation and taste at the posterior one-third of the tongue.

Cranial Nerve 10: Vagus Nerve

• Type: Sensory & Motor
• Functions:
  • Taste at the epiglottis.
  • Aids in swallowing, speaking, and coughing.

Cranial Nerve 11: Accessory Nerve

• Type: Motor
• Functions:
  • Innervates trapezius and sternocleidomastoid muscles.
  • Shoulder shrugging and head rotation.

Cranial Nerve 12: Hypoglossal Nerve

• Type: Motor
• Function: Tongue movement.

Summary

• Cranial nerves 3, 4, 6: Primarily involved in eye movement.
• The facial drawing serves as a mnemonic device to remember nerve functions.