Tags: Anatomical Structure.
The annulus of Zinn also known as the annular tendon 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 four of the six extraocular muscles omitting the inferior oblique muscle and superior oblique muscle.It can be used to divide the regions of the superior orbital fissure.The arteries surrounding the optic nerve are sometimes called the circle of Zinn-Haller (CZH).
