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1. [TA] A chamber or cavity to which are connected several chambers or passageways. 2. SYN: a. of heart. 3. That part of the tympanic cavity that lies immediately deep to the eardrum. 4. SYN: a. of middle nasal meatus. 5. In the lung, a subdivision of the alveolar duct from which alveolar sacs open. [L. entrance hall]
- accessory a. SYN: cor triatriatum.
- a. glottidis SYN: vestibule of larynx.
- a. of lateral ventricle [TA] portion of lateral ventricle of brain common to the frontal, occipital, and temporal horns. SYN: a. ventriculi lateralis [TA], a. ventriculus lateralis [TA].
- a. of lateral ventricle [TA] that portion of the lateral ventricle where the body (or central part), posterior horn, and temporal horn converge; it contains the choroid enlargement.
- left a. of heart [TA] a. of the left side of the heart which receives the blood from the pulmonary veins. SYN: a. cordis sinistrum [TA], a. pulmonale, a. sinistrum cordis.
- a. of middle nasal meatus [TA] the anterior expanded portion of the middle meatus of the nose, just above the vestibule. SYN: a. meatus medii nasalis [TA], a. meatus medii, a. (4), nasal a..
- a. pulmonale SYN: left a. of heart.
- right a. of heart [TA] right a., the a. of the right side of the heart that receives the blood from the venae cavae and coronary sinus. SYN: a. cordis dextrum [TA], a. dextrum cordis.
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atri·um 'ā-trē-əm n, pl atria -trē-ə also atri·ums an anatomical cavity or passage esp a chamber of the heart that receives blood from the veins and forces it into a ventricle or ventricles
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n. (pl. atria)
1. either of the two upper chambers of the heart. Their muscular walls are thinner than those of the ventricles; the left atrium receives oxygenated blood from the lungs via the pulmonary vein; the right atrium receives deoxygenated blood from the venae cavae. See also auricle.
2. any of various anatomical chambers into which one or more cavities open.
• atrial adj.
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atri·um (aґtre-əm) pl. aґtria [L., from Gr. atrion hall] a chamber; used in anatomy to designate a chamber affording entrance to another structure or organ. Usually used alone to designate an atrium of the heart (a. cordis). atrial adj
Atria of the heart.
Medical dictionary. 2011.