Radiology, Vol 185, 389-393, Copyright © 1992 by Radiological Society of North America
Intersegmental (intersublobar) septum of the lower lobe in relation to the pulmonary ligament: anatomic, histologic, and CT correlations
YM Berkmen, SR Drossman and CC Marboe
Department of Radiology, Columbia-Presbyterian Medical Center, New York, NY 10032-3784.
A thin horizontal linear area of hyperattenuation that extends laterally
from the mediastinal surface of the lung within the area between the
inferior pulmonary vein and the diaphragm is a common observation on
computed tomographic (CT) scans of the chest. To determine the anatomic
basis for this structure, the authors examined four normal human lungs (two
right and two left lungs) fixed in an inflated state at pathologic and
histologic examination and at CT. The structure in question was identified
in one right and two left lungs. The linear area of hyperattenuation seen
at CT is a septum of thin, loose intraparenchymal connective tissue that is
bounded medially by the base of the pulmonary ligament, where the two
sleeves of the visceral pleura appose one another, and laterally by a
vertically oriented vein. The septum was identified in 39 of 50 (78%)
normal chest CT scans. The pulmonary ligament often appeared to look like a
beak at the mediastinal side of the lung. The septum, when visible (n =
39), was bounded medially by the beak in 28 CT scans (72%) and laterally by
a vein in 24 scans (62%).
