The zonule of Zinn (/ˈtsɪn/) (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 collectively referred to as the suspensory ligaments of the lens, as they act like suspensory ligaments.
Zonule of Zinn
Anatomy of the anterior part of the human eye. "Suspensory ligaments" are labeled at left.
The upper half of a sagittal section through the front of the eyeball. (Zonule of Zinn visible near center.)
The ciliary epithelial cells of the eye probably synthesize portions of the zonules.[1]
Anatomy
The zonule of Zinn is split into two layers: a thin layer, which lines the hyaloid fossa, and a thicker layer, which is a collection of zonular fibers. Together, the fibers are known as the suspensory ligament of the lens.[2] The zonules are about 1–2 μm in diameter.[3]
The zonules attach to the lens capsule 2 mm anterior and 1 mm posterior to the equator, and arise of the ciliary epithelium from the pars plana region as well as from the valleys between the ciliary processes in the pars plicata.[4][5]
When colour granules are displaced from the zonules of Zinn (by friction against the lens), the irises slowly fade. In some cases those colour granules clog the channels and lead to glaucoma pigmentosa.
The zonules are primarily made of fibrillin, a connective tissue protein.[1] Mutations in the fibrillin gene lead to the condition Marfan syndrome, and consequences include an increased risk of lens dislocation.[1]
Clinical appearance
The zonules of Zinn are difficult to visualize using a slit lamp, but may be seen with exceptional dilation of the pupil, or if a coloboma of the iris or a subluxation of the lens is present.[6] The number of zonules present in a person appears to decrease with age.[3] The zonules insert around the outer margin of the lens (equator), both anteriorly and posteriorly.[7]
Function
Securing the lens to the optical axis and transferring forces from the ciliary muscle in accommodation. When colour granules are displaced from the zonules of Zinn, caused by friction of the lens, the iris can slowly fade. These colour granules can clog the channels and lead to glaucoma pigmentosa.
Additional images
Structures of the eye labeled
This image shows another labeled view of the structures of the eye
References
This article incorporates text in the public domain from page 1018 of the 20th edition ofGray's Anatomy(1918)
^ abcKaufman, Paul L.; Alm, Albert (2010). Adler's physiology of the eye (11th ed.). St. Louis, Mo: Mosby. pp. 145–146. ISBN978-0-323-05714-1.
^. Archived from the original on September 17, 2008. Retrieved January 12, 2008.[full citation needed]
^ abBornfeld, Norbert; Spitznas, Manfred; Breipohl, Winrich; Bijvank, Gerhard J. (1974). "Scanning electron microscopy of the zonule of Zinn". Albrecht von Graefes Archiv für Klinische und Experimentelle Ophthalmologie. 192 (2): 117–29. doi:10.1007/BF00410698. PMID 4548321. S2CID 23592537.
^Remington, Lee Ann (2012). Clinical anatomy and physiology of the visual system (3rd ed.). St. Louis: Elsevier/Butterworth-Heinemann. p. 97. ISBN978-1437719260.
^"2020–2021 BCSC Basic and Clinical Science Course™". www.aao.org.
^McCulloch, C (1954). "The zonule of Zinn: Its origin, course, and insertion, and its relation to neighboring structures". Transactions of the American Ophthalmological Society. 52: 525–85. PMC1312608. PMID 13274438.
^Farnsworth, P. N.; Mauriello, J. A.; Burke-Gadomski, P; Kulyk, T; Cinotti, A. A. (1976). "Surface ultrastructure of the human lens capsule and zonular attachments". Investigative Ophthalmology. 15 (1): 36–40. PMID 1245377.
External links
Diagram at unmc.edu
Diagram and overview at webschoolsolutions.com
Histology image: 08011loa – Histology Learning System at Boston University
zonule, zinn, zonule, zinn, zinn, membrane, ciliary, zonule, after, johann, gottfried, zinn, ring, fibrous, strands, forming, zonule, little, band, that, connects, ciliary, body, with, crystalline, lens, these, fibers, sometimes, collectively, referred, suspen. The zonule of Zinn ˈ t s ɪ n 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 collectively referred to as the suspensory ligaments of the lens as they act like suspensory ligaments Zonule of ZinnAnatomy of the anterior part of the human eye Suspensory ligaments are labeled at left The upper half of a sagittal section through the front of the eyeball Zonule of Zinn visible near center DetailsIdentifiersLatinzonula ciliarisTA98A15 2 05 015TA26795FMA58838Anatomical terminology edit on Wikidata Contents 1 Development 2 Anatomy 3 Clinical appearance 4 Function 5 Additional images 6 References 7 External linksDevelopment EditThe ciliary epithelial cells of the eye probably synthesize portions of the zonules 1 Anatomy EditThe zonule of Zinn is split into two layers a thin layer which lines the hyaloid fossa and a thicker layer which is a collection of zonular fibers Together the fibers are known as the suspensory ligament of the lens 2 The zonules are about 1 2 mm in diameter 3 The zonules attach to the lens capsule 2 mm anterior and 1 mm posterior to the equator and arise of the ciliary epithelium from the pars plana region as well as from the valleys between the ciliary processes in the pars plicata 4 5 When colour granules are displaced from the zonules of Zinn by friction against the lens the irises slowly fade In some cases those colour granules clog the channels and lead to glaucoma pigmentosa The zonules are primarily made of fibrillin a connective tissue protein 1 Mutations in the fibrillin gene lead to the condition Marfan syndrome and consequences include an increased risk of lens dislocation 1 Clinical appearance EditThe zonules of Zinn are difficult to visualize using a slit lamp but may be seen with exceptional dilation of the pupil or if a coloboma of the iris or a subluxation of the lens is present 6 The number of zonules present in a person appears to decrease with age 3 The zonules insert around the outer margin of the lens equator both anteriorly and posteriorly 7 Function EditSecuring the lens to the optical axis and transferring forces from the ciliary muscle in accommodation When colour granules are displaced from the zonules of Zinn caused by friction of the lens the iris can slowly fade These colour granules can clog the channels and lead to glaucoma pigmentosa Additional images Edit Structures of the eye labeled This image shows another labeled view of the structures of the eyeReferences Edit This article incorporates text in the public domain from page 1018 of the 20th edition of Gray s Anatomy 1918 a b c Kaufman Paul L Alm Albert 2010 Adler s physiology of the eye 11th ed St Louis Mo Mosby pp 145 146 ISBN 978 0 323 05714 1 Vision via the optic nerve CN II Archived from the original on September 17 2008 Retrieved January 12 2008 full citation needed a b Bornfeld Norbert Spitznas Manfred Breipohl Winrich Bijvank Gerhard J 1974 Scanning electron microscopy of the zonule of Zinn Albrecht von Graefes Archiv fur Klinische und Experimentelle Ophthalmologie 192 2 117 29 doi 10 1007 BF00410698 PMID 4548321 S2CID 23592537 Remington Lee Ann 2012 Clinical anatomy and physiology of the visual system 3rd ed St Louis Elsevier Butterworth Heinemann p 97 ISBN 978 1437719260 2020 2021 BCSC Basic and Clinical Science Course www aao org McCulloch C 1954 The zonule of Zinn Its origin course and insertion and its relation to neighboring structures Transactions of the American Ophthalmological Society 52 525 85 PMC 1312608 PMID 13274438 Farnsworth P N Mauriello J A Burke Gadomski P Kulyk T Cinotti A A 1976 Surface ultrastructure of the human lens capsule and zonular attachments Investigative Ophthalmology 15 1 36 40 PMID 1245377 External links EditDiagram at unmc edu Diagram at eye surgery uk com Diagram and overview at webschoolsolutions com Histology image 08011loa Histology Learning System at Boston University Portal Anatomy Retrieved from https en wikipedia org w index php title Zonule of Zinn amp oldid 1105557983, wikipedia, wiki, book, books, library,
