vein

1. any of the tubular vessels that convey oxygen-depleted blood to the heart

2. any of the hollow branching tubes that form the supporting framework of an insect's wing

3. any of the vascular strands of a leaf

4. a clearly defined mass of ore, mineral, etc., filling a fault or fracture, often with a tabular or sheetlike shape

5. a natural underground watercourse

Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

vein

[vān]

(anatomy)

A relatively thin-walled blood vessel that carries blood from capillaries to the heart in vertebrates.

(botany)

One of the vascular bundles in a leaf.

(geology)

A mineral deposit in tabular or shell-like form filling a fracture in a host rock.

(invertebrate zoology)

One of the thick, stiff ribs providing support for the wing of an insect.

A venous sinus in invertebrates.

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Vein

a mineral body filling a fissure in rock. Simple veins are single mineralized fissures; complex veins are clusters of interwoven fissures or of zones of fracturing or schist formation. According to their morphological details veins are called lenticular, chambered, saddle-reef, ladder, or feather. Veins that cut across the layers of enclosing rock are called intersecting veins; those that lie in conformity with the stratification and dip of the enclosing rock are called stratified. The length of veins of mineral products varies from 1 m or less to 200 km—for example, the veins of gold ore in California. In terms of dip some veins taper off close to the earth’s surface, and others, for example, the vein of the Kolar deposit in India, are worked at a depth of more than 3 km. A vein has a geological and a working thickness, the minimum thickness for exploiting the vein deposit. Depending on the value of the constituent minerals, the working thickness of a vein may vary from several centimeters to dozens of meters.

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References in periodicals archive

Tunneled-cuffed catheter implanted into the accessory hemiazygos vein because of occlusion of the left innominate vein.

Malposition of a hemodialysis catheter in the accessory hemiazygos vein

Ao= Aorta; Az= Azygos vein; HAz= Hemiazygos vein; IAz= Interazygos vein and T12= 12th thoracic vertebrae.

LBV= Left brachiocephalic vein; SVC= Superior vena cava; Ao= Aorta; Az= Azygos vein; AHA= Accessory hemiazygos vein; HAz= Hemiazygos vein and IAz= Interazygos vein.

These veins communicate with each other as well as the paired azygos lines and develop into the reaortic-aortic connections of the left lumbar and hemiazygos veins (Stranding).

Pre-aortic Inter-azygos Veins: Two Case Reports/ Venas Interacigos Pre-aorticas: Reporte de Dos Casos

Ozbek et al reported a case in which hemiazygos vein was absent.

The right subcardinal vein forms azygos vein and the left subcardinal vein forms hemiazygos vein. The left superior intercostal vein and accessory hemiazygos vein are derived from left posterior cardinal vein and this vein simultaneously forms upper part of azygos vein.

Study of azygos system and its variations

The exam revealed multiple collateral venous pathways, such as the azygos and hemiazygos veins, internal and lateral thoracic veins, and vertebral venous plexus.

Hypoxemia and Right-to-Left-Shunt in Patient with Antiphospholipid Syndrome: A Case Report with Multimodality Imaging Findings and Literature Review

It contains the thoracic part of the descending aorta, the azygos and the two hemiazygos veins, the vagus and splanchnic nerves, the esophagus, the thoracic duct, and some lymph glands.

Radiological profile of mediastinal masses with special reference to computed tomography