Accessory hemiazygos vein: Definition from Answers.com

Vein: Accessory hemiazygos vein

Diagram showing completion of development of the parietal veins. (Accessory hemiazygos vein visible at center-left.)

The venæ cavæ and azygos veins, with their tributaries.
Latin	vena hemiazygos accessoria
Gray's	subject #172 664
Drains to	hemiazygos vein, azygos vein

The accessory hemiazygos vein (vena azygos minor superior) is a vein on the left side of the vertebral column that generally drains the fifth through eighth intercostal spaces on the left side of the body.

Structure

The accessory hemiazygos vein varies inversely in size with the left superior intercostal vein.

It receives the posterior intercostal veins from the 4th, 5th, 6th, and 7th intercostal spaces between the left superior intercostal vein and highest tributary of the hemiazygos vein; the left bronchial vein sometimes opens into it.

It either crosses the body of the eighth thoracic vertebra to join the azygos vein or ends in the hemiazygos.

When this vein is small, or altogether absent, the left superior intercostal vein may extend as low as the fifth or sixth intercostal space.

Veins of the thorax and vertebral column (TA A12.3.01–04, 07, GA 7.664)

Thorax

Coronary

Coronary sinus	Great cardiac (Left marginal) · Posterior of the left ventricle · Oblique of the left atrium (Ligament of the left vena cava) · Middle cardiac

Small cardiac vein	Anterior cardiac (Right marginal)

Smallest cardiac veins	Right atrial veins · Right ventricular veins

Pulmonary

right inferior pulmonary vein · right superior pulmonary vein · left inferior pulmonary vein · left superior pulmonary vein

SVC

Brachiocephalic	internal thoracic (anterior intercostal, superior epigastric) · left superior intercostal · supreme · vertebral · subclavian (axillary: lateral thoracic, thoracoepigastric, dorsal scapular, external jugular) · pericardiacophrenic · internal jugular

Azygos	right superior intercostal · bronchial · intercostal/posterior intercostal 5-11 · accessory hemiazygos/hemiazygos · superior phrenic

Vertebral column

vertebral venous plexuses (external, internal) · spinal (posterior, anterior) · basivertebral · intervertebral

M: VAS

anat(a:h/u/t/a/l,v:h/u/t/a/l)/phys/devp/cell/prot

noco/syva/cong/lyvd/tumr, sysi/epon, injr

proc, drug(C2s+n/3/4/5/7/8/9)

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		American Heritage Stedman's Medical Dictionary. The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Read more
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