Trochlear nerve at a glance
- What it is
- The trochlear nerve (CN IV) is a motor nerve supplying the superior oblique muscle of the eye.
- Location
- It emerges from the dorsal midbrain below the inferior colliculus, winds around the brainstem, passes through the cavernous sinus and enters the orbit via the superior orbital fissure.
- Function
- It supplies the superior oblique, which depresses the eye (especially when adducted) and intorts it.
- Body system
- Nervous · paired (left and right)
- FMA ID
- FMA50882 (Foundational Model of Anatomy)
Key facts
- Cranial nerve IV.
- Only cranial nerve to exit dorsally and to decussate fully.
- Longest intracranial course of the cranial nerves, with the thinnest axon bundle.
Clinical relevance
Palsy causes vertical double vision, worse on looking down, and a compensatory head tilt away from the affected side.
Structures next to the trochlear nerve
The nearest named structures in the 3D model, measured from the centre of each part:
- Ophthalmic nerve · nervous
- Posterior communicating artery · cardiovascular
- Pituitary gland · endocrine
- Optic nerve · nervous
- Anterior cerebral artery · cardiovascular
- Anterior communicating artery · cardiovascular
- Precommunicating part of posterior cerebral artery · cardiovascular
- Communicating branch of nasociliary nerve with ciliary ganglion · nervous
- Amygdala · nervous
- Optic chiasm · nervous
References
- Foundational Model of Anatomy: Trochlear nerve (FMA50882). EMBL-EBI Ontology Lookup Service.
- OpenStax. Anatomy and Physiology 2e, §12.1 Basic Structure and Function of the Nervous System. Rice University, 2022.
- Mitsuhashi N. et al. (2009). BodyParts3D: 3D structure database for anatomical concepts. Nucleic Acids Research 37, D782–D785. Data © The Database Center for Life Science, CC BY 4.0.
Explore the whole body in the interactive 3D human anatomy model, or browse the A–Z list of human structures.