The common tendinous ring, also known as the annulus of Zinn, or annular tendon, is a ring of

fibrous tissue Fiber or fibre (from la, fibra, links=no) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate ...

surrounding the

optic nerve In neuroanatomy, the optic nerve, also known as the second cranial nerve, cranial nerve II, or simply CN II, is a paired cranial nerve that transmits visual information from the retina to the brain. In humans, the optic nerve is derived fro ...

at its entrance at the apex of the

orbit In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as ...

. It is the common origin of the four

recti muscles The extraocular muscles (extrinsic ocular muscles), are the seven extrinsic muscles of the human eye. Six of the extraocular muscles, the four recti muscles, and the superior and inferior oblique muscles, control movement of the eye and the oth ...

of the group of

extraocular muscles The extraocular muscles (extrinsic ocular muscles), are the seven extrinsic muscles of the human eye. Six of the extraocular muscles, the four recti muscles, and the superior and inferior oblique muscles, control movement of the eye and the othe ...

. It can be used to divide the regions of the superior orbital fissure. The

arteries An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry oxygenated blood; the two exceptions are the pu ...

surrounding the optic nerve form a vascular structure known as the circle of Zinn-Haller, or sometimes as the ''circle of Zinn''. The following structures pass through the tendinous ring (superior to inferior): * Superior division of the oculomotor nerve (CNIII) *

Nasociliary nerve The nasociliary nerve is a branch of the ophthalmic nerve, itself a branch of the trigeminal nerve (CN V). It is intermediate in size between the other two branches of the ophthalmic nerve, the frontal nerve and lacrimal nerve. Structure The na ...

(branch of

ophthalmic nerve The ophthalmic nerve (V1) is a sensory nerve of the face. It is one of three divisions of the trigeminal nerve (CN V). It has three branches that provide sensory innervation to the eye, the skin of the upper face, and the skin of the anterior sc ...

) * Inferior division of the oculomotor nerve (CNIII) *

Abducens nerve The abducens nerve or abducent nerve, also known as the sixth cranial nerve, cranial nerve VI, or simply CN VI, is a cranial nerve in humans and various other animals that controls the movement of the lateral rectus muscle, one of the extraocul ...

(CNVI) * Optic nerve

Parts

The common tendinous ring spans the superior orbital fissure and can be described as having two parts – an inferior tendon which gives origin to the inferior rectus muscle, and to part of the lateral rectus muscle; and a superior tendon which gives origin to the superior rectus muscle, and to part of the medial and lateral recti muscles.

Eponym

It is named for

Johann Gottfried Zinn Johann Gottfried Zinn () (December 6, 1727 – April 6, 1759) was a German anatomist and botanist and was a member of the Berlin Academy. Biography Johann Gottfried Zinn was born in Schwabach. Considering his short life span, Zinn made a gre ...

.J. G. Zinn. Descriptio anatomica oculi humani. Göttingen, B. Abrami Vandenhoeck, 1755. It should not be confused with the

zonule of Zinn The zonule of Zinn () (Zinn's membrane, ciliary zonule) (after Johann Gottfried Zinn) is a ring of fibrous strands forming a zonule (little band) that connects the ciliary body with the crystalline lens of the eye. These fibers are sometimes coll ...

, though it is named after the same person.

References

{{Authority control Histology Human eye anatomy