lung zone


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lung zone

A hypothetical region of the lung defined by the relationship between the degree of alveolar ventilation and pulmonary blood flow (perfusion). Three lung zones have been identified: I, ventilation exceeds perfusion; II, ventilation and perfusion are equal; and III, perfusion exceeds ventilation. Zone I is found in the upper lung field, where gravity impedes perfusion, and zone III in the inferior portion of the lung, where gravity assists perfusion.
See also: zone
References in periodicals archive ?
Caption: Figure 1: Posteroanterior chest X-ray demonstrating extensive ill- defined bilateral parenchymal opacities in the perihilar, mid, and lower lung zones.
Centrilobular type is more often found in upper lung zones (i.e., the posterior and apical segments of the upper lobes or the superior segments of the lower lobes) and is commonly associated with cigarette smoking [62].
Typically, chest radiograph in early stage shows bilateral and symmetric micronodular or reticulonodular shadow predominantly in mid and upper lung zones with sparing of costophrenic angles.
in more than half of the cases the tumour had invaded two or more lung zones however, 1/4th of cases were confined to the middle zone.
No statistically significant relation was seen when different lung zones were analyzed.
He had few bilateral crackles with decreased aeration in the lower lung zones. Photophobia was present with no focal neurological deficits.
Emphysema caused by alpha 1 deficiency is worse in the lower lung zones and can be markedly accelerated by cigarette smoking.
After four weeks of fluctuating pyrexia, a repeat chest X-ray showed new nodular shadowing throughout the mid and lower lung zones bilaterally, consistent with a diagnosis of miliary tuberculosis.
In healthy subjects, there was a prevalence of pulmonary flow in the lower lung zones. In CB patients with normal PAPm and high PAPm at rest pulmonary flow has tendency to redistribution to upper lung zones.
Briefly, the frontal chest x-ray radiograph was divided into six lung zones (left upper zone, left middle zone, left lower zone, right upper zone, right middle zone, and right lower zone), with the upper zone representing the area above the carina (including the apex), the middle zone from the carina to the level of inferior pulmonary veins, and the lower zone from the lower margin of the middle zone to the lung base.
Unilateral opacity occurred predominantly in the upper lung zones. Rapid progression of the lung infiltrate was found in six patients (patients 1-5 and 9).