The hyaloid canal (Cloquet's canal and Stilling's canal) is a small transparent canal running through the

vitreous body The vitreous body (''vitreous'' meaning "glass-like"; , ) is the clear gel that fills the space between the Lens (vision), lens and the retina of the eye, eyeball (the vitreous chamber) in humans and other vertebrates. It is often referred to as ...

from 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 system, visual information from the retina to the brain. In humans, the optic nerve i ...

disc (at the

punctum caecum A blind spot, scotoma, is an obscuration of the visual field. A particular blind spot known as the ''physiological blind spot'', "blind point", or ''punctum caecum'' in medical literature, is the place in the visual field that corresponds to t ...

) to the

lens A lens is a transmissive optical device that 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'') ...

. It is formed by an

invagination Invagination is the process of a surface folding in on itself to form a cavity, pouch or tube. In developmental biology, invagination of Epithelium, epithelial sheets occurs in many contexts during Animal embryonic development, embryonic developme ...

of the

hyaloid membrane The vitreous membrane (or hyaloid membrane or vitreous cortex) is a layer of collagen separating the vitreous humour from the rest of the eye. At least two parts have been identified anatomically. The posterior hyaloid membrane separates the rear ...

, which encloses the vitreous body. In the

fetus A fetus or foetus (; : fetuses, foetuses, rarely feti or foeti) is the unborn offspring of a viviparous animal that develops from an embryo. Following the embryonic development, embryonic stage, the fetal stage of development takes place. Pren ...

, the hyaloid canal contains a prolongation of the

central artery of the retina The central retinal artery (retinal artery) branches off the ophthalmic artery, running inferior to the optic nerve within its dural sheath to the eyeball. Structure The central retinal artery pierces the eyeball close to the optic nerve, sendi ...

, the

hyaloid artery The hyaloid artery is a branch of the ophthalmic artery, which is itself a branch of the internal carotid artery. It is contained within the optic stalk of the eye and extends from the optic disc through the vitreous humor to the lens. Usually ...

, which supplies blood to the developing lens. Once the lens is fully developed the hyaloid artery retracts and the hyaloid canal contains

lymph Lymph () is the fluid that flows through the lymphatic system, a system composed of lymph vessels (channels) and intervening lymph nodes whose function, like the venous system, is to return fluid from the tissues to be recirculated. At the ori ...

. The hyaloid canal appears to have no function in the adult eye, though its remnant structure can be seen. Contrary to initial belief, the hyaloid canal does not facilitate changes in the volume of the lens. The lens volume changes by less than 1% over its range of accommodation. Furthermore, lymph, being liquid, is incompressible, so even if the volume of the lens did change, the hyaloid canal could not compensate for it.

References

{{Authority control Human eye anatomy de:Arteria hyaloidea

See also

References