Lacrimal Punctum
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The lacrimal punctum (plural ''puncta'') or lacrimal point, is a minute opening on the summits of the
lacrimal papilla The lacrimal papilla is the small rise in the bottom (inferior) and top (superior) eyelid just before it ends at the corner of the eye closest to the nose. At the medial edge of it is the lacrimal punctum, a small hole that lets tears drain into th ...
e, seen on the margins of the
eyelid An eyelid is a thin fold of skin that covers and protects an eye. The levator palpebrae superioris muscle retracts the eyelid, exposing the cornea to the outside, giving vision. This can be either voluntarily or involuntarily. The human eyel ...
s at the lateral extremity of the
lacrimal lake The lacrimal lake is the pool of tears in the lower conjunctival cul-de-sac, which drains into the opening of the tear drainage system (the ''puncta lacrimalia''). The volume of the lacrimal lake has been estimated to be between 7 and 10 μL. ...
. There are two lacrimal puncta in the medial (inside) portion of each eyelid. Normally, the puncta dip into the lacrimal lake. Together, they function to collect tears produced by the
lacrimal gland The lacrimal glands are paired exocrine glands, one for each eye, found in most terrestrial vertebrates and some marine mammals, that secrete the aqueous layer of the tear film. In humans, they are situated in the upper lateral region of each or ...
s. The fluid is conveyed through the
lacrimal canaliculi The lacrimal canaliculi, (sing. canaliculus), are the small channels in each eyelid that drain lacrimal fluid, from the lacrimal puncta to the lacrimal sac. This forms part of the lacrimal apparatus that drains lacrimal fluid from the surface of ...
to the
lacrimal sac The lacrimal sac or lachrymal sac is the upper dilated end of the nasolacrimal duct, and is lodged in a deep groove formed by the lacrimal bone and frontal process of the maxilla. It connects the lacrimal canaliculi, which drain tears from the ey ...
, and thence via the
nasolacrimal duct The nasolacrimal duct (also called the tear duct) carries tears from the lacrimal sac of the eye into the nasal cavity. The duct begins in the eye socket between the maxillary and lacrimal bones, from where it passes downwards and backwards. The ...
to the inferior nasal meatus of the
nasal passage The nasal cavity is a large, air-filled space above and behind the nose in the middle of the face. The nasal septum divides the cavity into two cavities, also known as fossae. Each cavity is the continuation of one of the two nostrils. The nasal c ...
.


Additional images

File:Lacrimal punctum.jpg, A close up of a lacrimal punctum. File:Lower lacrimal punctum.jpg, Lower lacrimal punctum through slit lamp biomicroscope


See also

* Imperforate lacrimal punctum *
Lacrimal apparatus The lacrimal apparatus is the physiological system containing the Orbit (anatomy), orbital structures for tears, tear production and drainage.Cassin, B. and Solomon, S. ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishing Com ...
* Punctal plug


References


External links


Diagram and discussion at aafp.org
{{Authority control Human eye anatomy