Annulus of Zinn
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2008-05-28T07:59:05Z
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{{Infobox Anatomy |
Name = Annulus of Zinn |
Latin = annulus tendineus communis |
GraySubject = 227 |
GrayPage = 1022 |
Image = Eyemuscles.png |
Caption = ''Rectus muscles:'' <BR>2 = [[Superior rectus muscle|superior]], 3 = [[Inferior rectus muscle|inferior]], 4 = [[Medial rectus muscle|medial]], 5 = [[Lateral rectus muscle|lateral]]<br>''Oblique muscles:'' 6 = [[Superior oblique muscle|superior]], 8 = [[Inferior oblique muscle|inferior]]<br>''Other muscle:'' 9 = [[levator palpebrae superioris muscle|levator palpebrae superioris]]<br>''Other structures:'' 1 = Annulus of Zinn, 7 = [[Trochlea of superior oblique|Trochlea]], 10 = [[Tarsi|Superior tarsus]], 11 = [[Sclera]], 12 = [[Optic nerve]] |
Image2 = Eye orbit anterior.jpg |
Caption2 = ''Anterior view'' |
System = |
MeshName = |
MeshNumber = |
MeshName = |
MeshNumber = |
DorlandsPre = a_50 |
DorlandsSuf = 12143789 |
}}
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 (anatomy)|orbit]]. It is the origin for five of the six [[extraocular muscles]]. (Some sources only include four.<ref name="titleAnatomy Tables - Eye">{{cite web |url=http://anatomy.med.umich.edu/nervous_system/eye_tables.html |title=Anatomy Tables - Eye |accessdate=2008-03-17 |format= |work=}}</ref>)
It can be used to divide the regions of the [[superior orbital fissure]].<ref name="pmid17080461">{{cite journal |author=Shi X, Han H, Zhao J, Zhou C |title=Microsurgical anatomy of the superior orbital fissure |journal=Clin Anat |volume=20 |issue=4 |pages=362–6 |year=2007 |pmid=17080461 |doi=10.1002/ca.20391}}</ref>
The arteries surrounding the [[optic nerve]] are sometimes called the "circle of Zinn-Haller" ("CZH").<ref name="pmid10381675">{{cite journal |author=Ko MK, Kim DS, Ahn YK |title=Morphological variations of the peripapillary circle of Zinn-Haller by flat section |journal=Br J Ophthalmol |volume=83 |issue=7 |pages=862–6 |year=1999 |pmid=10381675 |doi= |url=http://bjo.bmj.com/cgi/pmidlookup?view=long&pmid=10381675}}</ref> This vascular structure is also sometimes called "circle of Zinn"<ref>{{Dorlands|c_36|12241137}}</ref>.
==Parts==
Some sources distinguish between these terms more precisely, with the annulus tendineus communis being the parent structure, divided into two parts: <ref name="titleeMedicine - Orbit Anatomy : Article by Guy J Petruzzelli">{{cite web |url=http://www.emedicine.com/Ent/topic4.htm#section~ExtraocularMuscles |title=eMedicine - Orbit Anatomy : Article by Guy J Petruzzelli |accessdate=2008-03-17 |format= |work=}}</ref>
* a lower, the ''ligament'' or ''tendon of Zinn'', which gives origin to the [[Rectus inferior]], part of the [[Rectus internus]], and the lower head of origin of the [[Rectus lateralis]].
* an upper, which gives origin to the [[Rectus superior]], the rest of the [[Rectus medialis]], and the upper head of the [[Rectus lateralis]]. This upper band is sometimes termed the ''superior tendon of Lockwood''. <ref>{{Dorlands|l_09|12490170}}</ref>
==Eponym==
It is named for [[Johann Gottfried Zinn]].<ref>{{WhoNamedIt|synd|3938}}</ref><ref>J. G. Zinn. Descriptio anatomica oculi humani. Göttingen, B. Abrami Vandenhoeck, 1755.</ref> It should not be confused with the [[Zonule of Zinn]], though it is named after the same person.
==References==
{{reflist|2}}
[[Category:Histology]]
[[Category:Eye]]
[[nl:Annulus tendineus communis]]