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Inferior branch of oculomotor nerve: anatomy, location and function

The inferior division of the oculomotor nerve supplies three extraocular muscles and carries parasympathetic fibres to the ciliary ganglion. Its motor fibres supply the medial rectus, inferior rectus and inferior oblique, and its parasympathetic fibres run in the nerve to the inferior oblique to the ciliary ganglion.

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Highlighted in the model: Inferior branch of oculomotor nerve. Click any part to read about it, or switch off “Highlight topic” to see the whole body. 3D data: BodyParts3D, © The Database Center for Life Science, CC BY 4.0; meshes simplified and recoloured. The model is an adult male.

Inferior branch of oculomotor nerve at a glance

What it is
The inferior division of the oculomotor nerve supplies three extraocular muscles and carries parasympathetic fibres to the ciliary ganglion.
Location
It arises from the oculomotor nerve in the front of the cavernous sinus or at the superior orbital fissure, passes through the common tendinous ring and runs below the optic nerve.
Function
Its motor fibres supply the medial rectus, inferior rectus and inferior oblique, and its parasympathetic fibres run in the nerve to the inferior oblique to the ciliary ganglion.
Body system
Nervous · paired (left and right)
FMA ID
FMA52577 (Foundational Model of Anatomy)

Key facts

  • Part of CN III.
  • Parasympathetic fibres serve the sphincter pupillae and ciliary muscle.

Clinical relevance

A complete oculomotor palsy gives a 'down and out' eye with ptosis and a dilated pupil; an isolated inferior-division lesion spares the eyelid but weakens adduction and depression and may dilate the pupil.

Structures next to the inferior branch of oculomotor nerve

The nearest named structures in the 3D model, measured from the centre of each part:

References

  1. Foundational Model of Anatomy: Inferior branch of oculomotor nerve (FMA52577). EMBL-EBI Ontology Lookup Service.
  2. OpenStax. Anatomy and Physiology 2e, §12.1 Basic Structure and Function of the Nervous System. Rice University, 2022.
  3. 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.