sac (sak) a pouch or bag.
Lacrimal sac
lacrimal sac,
air sacs alveolar s's.
allantoic sac the dilated portion of the allantois, becoming a part of the placenta in many mammals; it becomes the urachus in humans.
alveolar sacs the spaces into which the alveolar ducts open distally, and with which the alveoli communicate. 
)
Alveolar sacs (sacculi alveolares).
amniotic sac that formed by the amnion, containing the amniotic fluid.
chorionic sac that formed by the vertebrate chorion, surrounding the embryo, amniotic cavity, and amniotic sac and contributing to the fetal part of the placenta.
conjunctival sac the potential space, lined by conjunctiva, between the eyelids and eyeball.
dental sac the dense fibrous layer of mesenchyme surrounding the enamel organ and dental papilla.
endolymphatic sac the blind, flattened cerebral end of the endolymphatic duct.
gestational sac that comprising the extraembryonic membranes that envelop the embryo or fetus; in humans, that formed by the fused amnion and chorion.
heart sac pericardium.
hernial sac the peritoneal pouch enclosing a hernia.
Hilton's sac laryngeal saccule.
lacrimal sac the dilated upper end of the nasolacrimal duct.
yolk sac the extraembryonic membrane that connects with the midgut; at the end of the fourth week of development it expands into a pear-shaped vesicle (umbilical vesicle) connected to the body of the embryo by a long narrow tube (yolk stalk) . In mammals, it produces a complete vitelline circulation in the early embryo and then undergoes regression.
| lacrimal sac n. The upper portion of the nasolacrimal duct into which the two lacrimal ducts empty. Also called dacryocyst, tear sac. |
Lacrimal sac
The dilated upper end of the nasolacrimal duct in which the lacrimal ducts empty.
Mentioned in: Lacrimal Duct Obstruction
lacrimal sac,
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.
lacrimal
pertaining to tears.
lacrimal apparatus
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.
)
Nasolacrimal apparatus in the dog.By permission from McCurnin D, Poffenbarger EM, Small Animal Physical Diagnosis and Clinical Procedures, Saunders, 1991
lacrimal canaliculus
the lacrimal duct within the eyelid.
lacrimal caruncle
the rounded, often pigmented swelling at the medial canthus of the eye.
lacrimal cyst
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.
lacrimal 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.
lacrimal fossa
fossa in the medial wall of the orbital rim which houses the lacrimal sac.
lacrimal gland
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.
lacrimal lake
the recess between the lids at the nasal commissure of the eye where the tears collect.
lacrimal pump
contraction of the orbiculari oculi muscle creates pressure on the lacrimal sac which causes tears to drain from the lacrimal lake.
lacrimal punctum
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.
lacrimal reflex
tear production caused by irritation of the cornea and conjunctiva.
lacrimal sac
the distended proximal end of the nasolacrimal duct into which the lacrimal ducts empty.
lacrimal sinus
an excavation of the lacrimal bone which communicates with the maxillary sinus in some species.
lacrimal system
see lacrimal apparatus (above).
sac
a pouch; a baglike organ or structure. See also conjunctival sac.
air sac
1. alveolar sac.
2. one of the large air-filled diverticula of the respiratory system of birds. See also air sacs.
allantoic sac
see allantois.
alveolar s's
the spaces into which the alveolar ducts open distally, and with which the alveoli communicate.
anal sac
see anal sacs.
endolymphatic sac
the blind, flattened cerebral end of the endolymphatic duct.
heart sac
the pericardium.
hernial sac
the peritoneal pouch that encloses a herniated viscus or mesentery.
lacrimal sac
see lacrimal sac.
paranal sac
see anal sacs.
pleural sac
the pleura-lined cavity which contains the lung.
ruminal sac
one of the dorsal and ventral sacs of the rumen which are themselves further subdivided to create a caudodorsal sac and a caudoventral sac.
yolk sac
the extraembryonic membrane connected with the midgut; in vertebrates other than true mammals, it contains a yolk mass. See also yolk sac.
lacrimal apparatus
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
lacrimal apparatus
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.
)
Fig. L1 Lacrimal apparatus
How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content.
| ?Page tools | ||
|---|---|---|
|