Overview
Role
- Somatic motor - eye intorsion and depression (through contraction of the contralateral superior oblique).
Trochlear Nerve Palsy
Abnormalities
- Eye deviation upward and rotation outward
- Vertical diplopia
- Inability to look down and in - difficulty descending stairs
- Head tilting away from the side of the lesion
Causes of Trochlear Nerve Palsy
- Congenital absence
- Closed head injury
Motor Pathway
Cortical Centre
Primary motor cortex (frontal lobe)
Primary motor cortex (frontal lobe)
Trochlear Nucleus
Tegmentum (midbrain)
Tegmentum (midbrain)
Decussation
Upper medulla
Upper medulla
Foramen
Superior orbital fissure
Superior orbital fissure
Muscle
Superior oblique
Superior oblique
Overview
The trochlear nerve is the longest intracranial nerve in the body and has the least axons, making it the most susceptible to stretch damage in the case of closed head trauma.
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