The annulus of Zinn, also known as the annular tendon, circle of Zinn-Haller or common tendinous ring, is a ring of fibrous tissue surrounding the optic nerve at its entrance at the apex of the orbit. It is the origin for five of the six extraocular muscles.

Named after Johann Gottfried Zinn.

External links

• eMedicine

Histology | Eye | Eponymous anatomical structures