canaliculi

Canaliculi

Also known as lacrimal ducts, these tube-like structures carry the tears from the eyes to the lacrimal sac.

Mentioned in: Dacryocystitis

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canaliculus

[kan′əlik′yələs] pl. canaliculi

Etymology: L, little channel

a very small tube or channel, such as the microscopic haversian canaliculi throughout bone tissue.

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canaliculus [kan″ah-lik´u-lus] (pl. canali´culi) (L.)

an extremely narrow tubular passage or channel. adj., adj canalic´ular.

bile canaliculi fine tubular channels forming a three-dimensional network within the parenchyma of the liver. They join to form the bile ductules and eventually the hepatic duct.

bone canaliculi branching tubular passages radiating like wheel spokes from each bone lacuna to connect with the canaliculi of adjacent lacunae, and with the haversian canal.

lacrimal canaliculus the short passage in an eyelid, beginning at the lacrimal point and draining tears from the lacrimal lake to the lacrimal sac; called also lacrimal duct. See also lacrimal apparatus.

mastoid canaliculus a small channel in the temporal bone transmitting the auricular branch of the vagus nerve.

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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

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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