Remy J, Lemaitre L, Smith M
Radiologe. 1981 Jul;21(7):324-9.
Depending on the size of the subcarinal and retrobronchial recess the medial wall of the right and perhaps the left main bronchus can be recognized. The medial extension of the recess is very variable. On lateral films with slight anterior rotation of the right shoulder, the posterior wall of the right main bronchus can be shown in 97% of patients. Awareness of this recess and its boundaries is essential for diagnosis of subcarinal and tracheobronchial node enlargement. The following 4 signs will assist in diagnosis: 1. The dorsal margin of enlarged nodes may be recognized posterior and inferior to the carina. 2. The posterior wall of the right main bronchus can no longer be seen. 3. The medial wall of the right main bronchus can no longer be seen. 4. Clearer demonstration of the right main bronchus or bronchus intermedius occurs, due to an "air bronchogram" effect. Due to the application of these 4 signs, enlargements of the subcarinal or tracheobronchial nodes can be recognized, at a stage where the tracheal bifurcation is not yet splayed, and when the nodes have not yet caused bronchostenosis.
根据隆突下和支气管后间隙的大小，可识别右主支气管或许还有左主支气管的内侧壁。该间隙的内侧延伸范围变化很大。在右肩轻度向前旋转的侧位片上，97%的患者可显示出右主支气管的后壁。了解这个间隙及其边界对于诊断隆突下和气管支气管淋巴结肿大至关重要。以下4个征象有助于诊断：1. 肿大淋巴结的背侧边缘可在隆突后方和下方被识别。2. 右主支气管的后壁不再可见。3. 右主支气管的内侧壁不再可见。4. 由于“空气支气管造影”效应，右主支气管或中间支气管显示得更清晰。应用这4个征象，在气管分叉尚未增宽且淋巴结尚未引起支气管狭窄的阶段，就能识别出隆突下或气管支气管淋巴结肿大。
