Mittendorf's Dot
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The hyaloid artery is a branch of the
ophthalmic artery The ophthalmic artery (OA) is an artery of the head. It is the first branch of the internal carotid artery distal to the cavernous sinus. Branches of the ophthalmic artery supply all the structures in the orbit around the eye, as well as some st ...
, which is itself a branch of the
internal carotid artery The internal carotid artery (Latin: arteria carotis interna) is an artery in the neck which supplies the anterior circulation of the brain. In human anatomy, the internal and external carotids arise from the common carotid arteries, where these b ...
. It is contained within the optic stalk of the eye and extends from the
optic disc The optic disc or optic nerve head is the point of exit for ganglion cell axons leaving the eye. Because there are no rods or cones overlying the optic disc, it corresponds to a small blind spot in each eye. The ganglion cell axons form the ...
through the
vitreous humor The vitreous body (''vitreous'' meaning "glass-like"; , ) is the clear gel that fills the space between the lens and the retina of the eyeball (the vitreous chamber) in humans and other vertebrates. It is often referred to as the vitreous humor ...
to the
lens A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...
. Usually fully regressed before
birth Birth is the act or process of bearing or bringing forth offspring, also referred to in technical contexts as parturition. In mammals, the process is initiated by hormones which cause the muscular walls of the uterus to contract, expelling the f ...
, its purpose is to supply nutrients to the developing lens in the growing
fetus A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal deve ...
. During the tenth week of development in humans (time varies depending on species), the lens grows independent of a blood supply and the hyaloid artery usually regresses. Its proximal portion remains as the central artery of the
retina The retina (from la, rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then ...
. Regression of the hyaloid artery leaves a clear central zone through the vitreous humor, called the
hyaloid canal Hyaloid canal (Cloquet's canal and Stilling's canal) is a small transparent canal running through the vitreous body from the optic nerve disc to the lens. It is formed by an invagination of the hyaloid membrane, which encloses the vitreous body ...
or Cloquet's canal. Cloquet's canal is named after the French physician
Jules Germain Cloquet Jules Germain Cloquet (18 December 1790 – 23 February 1883) was a French physician and surgeon who was born and practiced medicine in Paris. His older brother, Hippolyte Cloquet (1787-1840) and his younger nephew Ernest Cloquet (1818-1855) w ...
(1790–1883) who first described it. Occasionally the artery may not fully regress, resulting in the condition ''persistent hyaloid artery''. More commonly, small remnants of the artery may remain. Free remnants can sometimes be seen as "
floater Floaters or eye floaters are sometimes visible deposits (e.g., the shadows of tiny structures of protein or other cell debris projected onto the retina) within the eye's vitreous humour ("the vitreous"), which is normally transparent, or betwee ...
s". An anterior remnant of the hyaloid artery can be seen in some people as ''Mittendorf's dot'', a small pinpoint-like scar on the posterior surface of the lens.Lee Ann Remington, Clinical Anatomy of the Visual System, 2005 p. 124 A posterior remnant may be seen where the artery left the optic disc, and is known as
Bergmeister's papilla Bergmeister's papilla arises from the centre of the optic disc, consists of a small tuft of fibrous tissue and represents a remnant of the fetal hyaloid artery. The hyaloid artery provides nutrition to the lens A lens is a transmissive ...
.


See also

*
Hyaline A hyaline substance is one with a glassy appearance. The word is derived from el, ὑάλινος, translit=hyálinos, lit=transparent, and el, ὕαλος, translit=hýalos, lit=crystal, glass, label=none. Histopathology Hyaline cartilage is ...


Notes


External links


The Vitreous Humor
at TedMontgomery.com

at
Straight Dope "The Straight Dope" was a question-and-answer newspaper column written under the pseudonym Cecil Adams. Contributions were made by multiple authors, and it was illustrated (also pseudonymously) by Slug Signorino. It was first published in 1973 i ...
Arteries {{circulatory-stub