lacrimal sac(redirected from tear sac)
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air s's (alveolar s's) the spaces into which the alveolar ducts open distally, and with which the alveoli communicate; see also lung.
amniotic sac the sac formed by the amnion, enclosing the fetus suspended in amniotic fluid; popularly known as the bag of waters.
conjunctival sac the potential space, lined by conjunctiva, between the eyelids and the eyeball.
endolymphatic sac the blind, flattened cerebral end of the endolymphatic duct.
hernial sac the peritoneal pouch that encloses protruding intestine.
lacrimal sac the dilated upper end of the nasolacrimal duct; see also lacrimal apparatus.
yolk sac the extraembryonic membrane connected with the midgut; in vertebrates below true mammals, it contains a yolk mass.
the dilated upper portion of the nasolacrimal duct into which the two lacrimal canaliculi empty.
the upper end of each of the two nasolacrimal ducts. Each sac is lodged in a deep groove formed by the lacrimal bone and the frontal process of the maxilla. The sac is ovoid and about 13 mm long. Its upper end is closed and rounded, its lower end continuous with the nasolacrimal duct. The lacrimal sacs fill with tears secreted by the lacrimal glands and conveyed through the lacrimal ducts.
lac·ri·mal sac(lak'ri-măl sak) [TA]
lacrimal sacThe small bag lying under the tissues just inwards and below the inner corner of the eye. Tears drain into the lacrimal sac before being discharged down the nasolacrimal duct into the nose.
The dilated upper end of the nasolacrimal duct in which the lacrimal ducts empty.
Mentioned in: Lacrimal Duct Obstruction
The system involved in the production and conduction of tears. It consists of the lacrimal gland and accessory lacrimal glands (glands of Krause and Wolfring); the eyelid margins; and the two puncta lacrimae. Each punctum is a small round or oval aperture situated on a slight elevation at the inner end of the upper and lower lid margin (lacrimal papilla) and forms the entrance to the canaliculi. Each canaliculus consists of a vertical portion of about
The system involved in the production and conduction of tears. It consists of the lacrimal gland and accessory lacrimal glands (glands of Krause and Wolfring); the eyelid margins; and the two puncta lacrimae. Each punctum is a small round or oval aperture situated on a slight elevation at the inner end of the upper and lower lid margin (lacrimal papilla) and forms the entrance to the canaliculi. Each canaliculus consists of a vertical portion of about 2 mm long and then bends inward for some 8 mm, the upper one being slightly shorter. The canaliculi pierce the lacrimal fascia (i.e. the periorbita covering the lacrimal sac or tear sac) and unite (forming the common canaliculus) to enter a small diverticulum of the sac called the sinus of Maier. The lacrimal sac is closed above and open below where it is continuous with the nasolacrimal duct which extends over some 1.5 cm in length to Hasner's valve (or Bianchi's valve or plica lacrimalis) (folds of mucous membrane) at the inferior meatus of the nose. The inferior opening of the duct is called the ostium lacrimale (Fig. L1). See dacryocystitis; epiphora; lacrimal fistula; fossa for the lacrimal sac; Sjögren's syndrome; tear duct; dye dilution test; Jones II test; valve of Krause.
pertaining to tears.
a group of organs concerned with the production and drainage of tears; it is a nutritive and protective device that helps keep the eye moist and free of dust and other irritating particles. Includes lacrimal gland, accessory lacrimal glands, third eyelid glands and the nasolacrimal duct.
the lacrimal duct within the eyelid.
the rounded, often pigmented swelling at the medial canthus of the eye.
congenital displacement of lacrimal tissue results in subconjunctival cysts.
lacrimal drainage system
the structures concerned with tear collection; includes lacrimal lake, puncta, canaliculi, sac and nasolacrimal duct.
there are two of these minute ducts draining tears from the conjunctiva, via the lacrimal puncta, into the lacrimal sac. Called also lacrimal canaliculus.
lacrimal duct irrigator
a 20 gauge, blunt-pointed, straight or curved cannula with a needle attachment so that it can be attached directly to a syringe nozzle.
fossa in the medial wall of the orbital rim which houses the lacrimal sac.
contained in a pad of fat in the dorsolateral part of the orbital cavity and drains into the conjunctival sac via many excretory ducts. The secretion is largely watery tears, but in the pig is mucus. May develop adenitis.
lacrimal gland anomalies
failure of patency of the duct, supernumerary opening of the duct and ductal ectasia recorded.
lacrimal gland atrophy
part of the syndrome of keratoconjunctivitis sicca.
imperforate lacrimal puncta
see imperforate punctum.
the recess between the lids at the nasal commissure of the eye where the tears collect.
contraction of the orbiculari oculi muscle creates pressure on the lacrimal sac which causes tears to drain from the lacrimal lake.
there is one on each eyelid close to the medial canthus. Each drains tears from the conjunctival sac into the lacrimal duct in the same eyelid. The tears then pass to the lacrimal sac and into the nasolacrimal duct. See also punctum.
tear production caused by irritation of the cornea and conjunctiva.
the distended proximal end of the nasolacrimal duct into which the lacrimal ducts empty.
an excavation of the lacrimal bone which communicates with the maxillary sinus in some species.
see lacrimal apparatus (above).
a pouch; a baglike organ or structure. See also conjunctival sac.
1. alveolar sac.
2. one of the large air-filled diverticula of the respiratory system of birds. See also air sacs.
the spaces into which the alveolar ducts open distally, and with which the alveoli communicate.
see anal sacs.
the blind, flattened cerebral end of the endolymphatic duct.
the peritoneal pouch that encloses a herniated viscus or mesentery.
see lacrimal sac.
see anal sacs.
the pleura-lined cavity which contains the lung.
one of the dorsal and ventral sacs of the rumen which are themselves further subdivided to create a caudodorsal sac and a caudoventral sac.
the extraembryonic membrane connected with the midgut; in vertebrates other than true mammals, it contains a yolk mass. See also yolk sac.