Lacrimal sac

Lacrimal sac
The lacrimal apparatusis shown through dissection on the left side.
The lacrimal sac has been opened showing internal organization as well as the naso-lacrymal duct.
Details
Artery	angular artery
Identifiers
Latin	saccus lacrimalis
Dorlands /Elsevier	s_01/12717293
TA	A15.2.07.068
FMA	20289
*Anatomical terminology* [edit on Wikidata]

The lacrimal sac or lachrymal sac^[1] 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 eye's surface, and the nasolacrimal duct, which conveys this fluid into the nasal cavity.

Structure

It is oval in form and measures from 12 to 15 mm. in length; its upper end is closed and rounded; its lower is continued into the nasolacrimal duct.

Its superficial surface is covered by a fibrous expansion derived from the medial palpebral ligament, and its deep surface is crossed by the lacrimal part of the Orbicularis oculi, which is attached to the crest on the lacrimal bone.

Histology

Like the nasolacrimal duct, the sac is lined by stratified columnar epithelium with mucus-secreting goblet cells, with surrounding connective tissue. The Lacrimal Sac also drains the eye of any debris, bacteria, dirt, etc.

Function

This is mainly for high amounts of tears, in which the lacrimal sac pumps inward and outward driven by the orbicularis muscle during blinking.

Clinical significance

The lacrimal sac can be pictured by dacrocystography, which is injecting radiocontrast into it and performing X-ray imaging of it.

Additional images

Medial wall of left orbit.
Left orbicularis oculi, seen from behind.
The lacrimal apparatus. Right side. (Lacrimal sac visible at upper right.)
The tarsi and their ligaments. Right eye; front view. (Lacrimal sac visible at middle right.)

References

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)

↑ Dr. Johannes Sobotta (1909). Sobotta's Atlas and Textbook of Human Anatomy. Philadelphia.

The orbit of the eye

Bones	Frontal bone Zygomatic bone Maxillary bone Sphenoid bone Ethmoid bone Palatine bone Lacrimal bone

Muscles	Superior rectus muscle Inferior rectus muscle Lateral rectus muscle Medial rectus muscle Superior oblique muscle Trochlea of superior oblique Inferior oblique muscle

Eyelid	Levator palpebrae superioris muscle Tarsus Medial palpebral ligament Epicanthic fold Meibomian gland Ciliary glands Eyelash Palpebral fissure Canthus Gland of Zeis

Lacrimal apparatus	Krause's glands Lacrimal canaliculi Lacrimal caruncle Lacrimal gland Lacrimal lake Lacrimal papilla Lacrimal punctum Lacrimal sac Nasolacrimal duct

Other	Eyebrow Conjunctiva Plica semilunaris Orbital septum Periorbita Suspensory ligament of eyeball Tenon's capsule

This article is issued from Wikipedia - version of the Friday, November 21, 2014. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.