Common tendinous ring (annulus of Zinn)
Anulus tendineus communis
Sensory (eye & ear)Deep musclesHeadLeft and right
View left in 3D View right in 3D
- What it is
- A fibrous ring at the apex of the orbit surrounding the optic canal and the middle of the superior orbital fissure.
- Function
- Gives origin to the four rectus muscles; the optic nerve, ophthalmic artery, oculomotor, abducens and nasociliary nerves pass through it.
- Size
- About 6-7 mm across.
- Clinical note
- Pressure on structures inside it causes the orbital apex syndrome: vision loss plus paralysis of eye movements.