Cranial Nerve, Physiology

1. Cranial
Nerves
Dr. Anupam Mittal
MBBS, MD
King George’s Medical University, Lucknow

2. Cranial Nerves
• Twelve pairs of cranial nerves are
associated with the brain
• The first two pairs attach to the
forebrain, and the rest are associated
with the brain stem.
• Other than the vagus nerves, which
extend into the abdomen, cranial
nerves serve only head and neck
structures.
• Divides into:
• Sensory nerves
• Motor Nerves
• Mixed Nerves

5. I. Olfactory Nerve
Component: Sensory
Function: Smell
Origin: Olfactory epithelium
Pass through: Opening in cribriform plate of
ethmoid
Applied Anatomy:- Fracture of ethmoid bone or
lesions of olfactory fibers may result in partial or total
loss of smell, a condition known as anosmia

6. II. Optic
Nerve
Component: Sensory
Function: Vision
Origin: Rises from the retina
and back of the eye ball
Pass through: Optic canal

7. III. Oculomotor
Nerve
Component:
Motor : Superior Rectus Muscle, Medial Rectus Muscle, Inferior Rectus Muscle,
Inferior Oblique Musle, Levator palpebrae superioris
Function:
• Rises upper eyelids
• Turn eyeball upward, downward & medially
• Constrict pupil
• Accommodate the eyes
Origin: Anterior surface of the midbrain
Pass through: Superior orbital fissure

9. IV. Trochlear Nerve
Component: Motor
Function: Traction of eyeball laterally and downward
Origin: Posterior surface of the midbrain
Pass through: Superior orbital fissure

10. Component: Sensory
Function:
• Cornea
• Skin of forehead
• Face
• Mandible
Origin: Anterior aspect of the pones
Pass through: Foramen Rotundum
V. Trigeminal Nerve

11. VI. Abducent Nerve
Component: Motor
Function: Lateral Rectus muscles of eyeball,
turn eye laterally
Origin: Foramen Rotundum
Pass through: Superior orbital fissure

12. VII. Facial
Nerve
Component: Motor
Function: Muscle of face,
cheek, scalp and stapedius
muscle of middle ear
Pass through:
Stylomastoid Foramen

13. VIII. Vestibulocochlear
Nerve
Component: Sensory
Function: Position and Movement of head, Hearing
Pass through: Internal acoustic meatus

15. IX.
Glossopharyngeal
Nerve
Component: Motor
Function: Assist
swallowing, Parotid salivary
gland
Pass through: Jugular
Foramen

16. X. Vagus
Nerve
Component: Motor
Function:
Constrictor muscles of pharynx
and intrinsic muscles of larynx;
Involuntary muscle of trachea
and bronchi, heart, alimentary
tract from pharynx to splenic
flexure of colon; liver and
pancreas
Pass through: Jugular foramen

17. XI. Accessory
Nerve
Component: Motor
Function:
Muscle of soft palate, pharynx,
and larynx
Sternocleidomastoid and
trapezium muscle
Pass through: Jugular
Foramen

18. Component: Motor
Function:
Muscle of tongue
controlling its shape and
movement
Pass through:
Hypoglossal canal
XII.
Hypoglossal
Nerve