Cranial nerves
The cranial nerves form part of the peripheral nervous system and
originate from the brain.
Olfactory (I)
Function Smell
Test
Identify a familiar odour
Abnormal signs
Partial or total loss of smell Altered or increased sense of smell
Optic (II)
Function Sight
Test
Visual acuity: read with one eye covered
Peripheral vision: detect objects or movement from the corner of the
eye with the other eye covered
Abnormal signs
Visual fields defects, loss of visual acuity, colour-blind
Oculomotor (III)
Function
Movement of eyelid and eyeball, constriction of pupil, lens
accommodation
, Test
Follow the examiner’s finger, which moves up and down and side to
side, keeping the head in mid-position
Abnormal signs
Squint, ptosis, diplopia, pupil dilation
Trochlear (IV)
Function
Movement of eyeball upwards
Test
As for oculomotor
Abnormal signs
Diplopia, squint
Trigeminal (V)
Function
Mastication, sensation for eye, face, sinuses and teeth
Test
Test fascial sensation ,Clench teeth
Abnormal signs
Trigeminal neuralgia, loss of mastication and sensation in eye, face,
sinuses and teeth
The cranial nerves form part of the peripheral nervous system and
originate from the brain.
Olfactory (I)
Function Smell
Test
Identify a familiar odour
Abnormal signs
Partial or total loss of smell Altered or increased sense of smell
Optic (II)
Function Sight
Test
Visual acuity: read with one eye covered
Peripheral vision: detect objects or movement from the corner of the
eye with the other eye covered
Abnormal signs
Visual fields defects, loss of visual acuity, colour-blind
Oculomotor (III)
Function
Movement of eyelid and eyeball, constriction of pupil, lens
accommodation
, Test
Follow the examiner’s finger, which moves up and down and side to
side, keeping the head in mid-position
Abnormal signs
Squint, ptosis, diplopia, pupil dilation
Trochlear (IV)
Function
Movement of eyeball upwards
Test
As for oculomotor
Abnormal signs
Diplopia, squint
Trigeminal (V)
Function
Mastication, sensation for eye, face, sinuses and teeth
Test
Test fascial sensation ,Clench teeth
Abnormal signs
Trigeminal neuralgia, loss of mastication and sensation in eye, face,
sinuses and teeth
