| Common tendinous ring | |
|---|---|
 Rectus muscles: 2 = superior, 3 = inferior, 4 = medial, 5 = lateral Oblique muscles: 6 = superior, 8 = inferior Other muscle: 9 = levator palpebrae superioris Other structures: 1 = Common tendinous ring, 7 = Trochlea, 10 = Superior tarsus, 11 = Sclera, 12 = Optic nerve | |
 Anterior view | |
| Details | |
| Identifiers | |
| Latin | anulus tendineus communis |
| TA98 | A15.2.07.015 |
| TA2 | 2047 |
| FMA | 49071 |
| Anatomical terminology | |
The common tendinous ring, also known as the annulus of Zinn or annular tendon, is a ring of fibrous tissue surrounding the optic nerve at its entrance at the apex of the orbit. It is the common origin of the four recti muscles of the group of extraocular muscles.
It can be used to divide the regions of the superior orbital fissure.[1]
The arteries surrounding the optic nerve form a vascular structure known as the circle of Zinn-Haller, or sometimes as the circle of Zinn.[2]
The following structures pass through the tendinous ring (superior to inferior):
- Superior division of the oculomotor nerve (CNIII)
- Nasociliary nerve (branch of ophthalmic nerve)
- Inferior division of the oculomotor nerve (CNIII)
- Abducens nerve (CNVI)
- Optic nerve
- ^ Shi X, Han H, Zhao J, Zhou C (2007). "Microsurgical anatomy of the superior orbital fissure". Clin Anat. 20 (4): 362–6. doi:10.1002/ca.20391. PMID 17080461. S2CID 43849585.
- ^ Ko MK, Kim DS, Ahn YK (1999). "Morphological variations of the peripapillary circle of Zinn-Haller by flat section". Br J Ophthalmol. 83 (7): 862–6. doi:10.1136/bjo.83.7.862. PMC 1723100. PMID 10381675.