[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Radiology](https://durgical.com/en/radiology/) › [Chest](https://durgical.com/en/radiology/areas/chest/) › Lobar collapse (atelectasis) on the chest X-ray # Lobar collapse (atelectasis) on the chest X-ray - Finding When a lobe loses its air it shrinks and turns white, and the structures around it are pulled toward it. Each lobe collapses in its own pattern. Updated Nov 12, 2026 ## Key points - Collapse = opacity plus volume loss: structures move toward it. - Golden S sign: right upper lobe collapse around a central mass. - Left upper lobe collapse: veil-like haze on the PA, not a sharp opacity. - Always look behind the heart for left lower lobe collapse. - Adult smoker with collapse: CT and bronchoscopy for a tumour. ## What it is Atelectasis is loss of air from part of the lung with loss of volume. The airless lobe becomes white, and because it is smaller it pulls on its neighbours: the fissures move toward it, the hilum and the trachea shift to its side, the hemidiaphragm rises and the remaining lobes over-expand. In adults the most important cause is a blocked bronchus (tumour, mucus plug, a tube in the wrong place); in children, an inhaled foreign body. Each lobe falls in a predictable direction, so the shape of the opacity and the borders it removes tell which lobe has collapsed. ## What it looks like - Direct signs: displaced fissure, crowded vessels and bronchi, increased density of the lobe. - Indirect signs: hilum, trachea and mediastinum pulled toward it, raised hemidiaphragm, crowded ribs, over-expansion of other lobes. - Right upper lobe: dense right upper zone with the horizontal fissure pulled up; a central mass makes the edge an S (Golden S sign). - Left upper lobe: a veil-like haze over the left lung with a lost left heart border; air around the aortic arch (Luftsichel sign). - Right middle lobe: right heart border lost; on the lateral view a thin wedge between the fissures. - Lower lobes: a triangular opacity behind the heart or at the base, with the hemidiaphragm (and on the left the descending aorta) lost. ## Why it looks that way - Obstructive: air beyond a blocked bronchus is absorbed into the blood and the lobe empties. - Passive or compressive: an effusion, pneumothorax or large mass squeezes the lung. - Others: scarring (cicatricial), surfactant loss (adhesive) and shallow breathing after surgery (small plate-like basal lines). ## Differential and pitfalls - Consolidation keeps volume; collapse loses it. Look for what has moved. - White hemithorax with shift toward it: whole-lung collapse (check the endotracheal tube and the main bronchus). - An adult smoker with lobar collapse has an obstructing tumour until proven otherwise. - A child with sudden cough or wheeze and collapse or air trapping: suspect an inhaled foreign body. - Left lower lobe collapse hides behind the heart; always look through the heart on a well-exposed film. ## Next step - Ventilated patient: check the endotracheal tube tip first; a tube in the right main bronchus collapses the left lung. - Postoperative plate atelectasis: physiotherapy, mobilisation and pain control; no further imaging if the patient improves. - Adult with lobar collapse not explained by a mucus plug: contrast CT of the chest to find an obstructing lesion. - Suspected mucus plug, foreign body or endobronchial tumour: bronchoscopy, diagnostic and therapeutic. - Whole-lung collapse with hypoxia: urgent senior review. ## Test yourself Think of the answer, then tap the question to see it. ## Which signs show that an opacity is collapse rather than consolidation? Signs of volume loss: shifted fissure, hilum or trachea pulled toward it, raised hemidiaphragm, crowded vessels and over-expanded other lobes. ## What does the Golden S sign indicate? Right upper lobe collapse with a central hilar mass: the horizontal fissure is concave laterally and bulges outward medially over the mass, forming a reversed S. ## How does left upper lobe collapse look on a PA film? As a hazy veil over the left hemithorax with the left heart border lost, sometimes with a crescent of air beside the aortic arch. ## In an intubated patient with a white left lung and shift to the left, what should you check first? The endotracheal tube tip: if it has gone down the right main bronchus, the left lung is not ventilated and collapses. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/radiology/lobar-collapse-on-the-chest-x-ray/) ## Connections ## Related 6 - [The silhouette sign: which lobe is it?](https://durgical.com/en/radiology/the-silhouette-sign-which-lobe-is-it/) - [Consolidation and air bronchograms](https://durgical.com/en/radiology/consolidation-and-air-bronchograms/) - [Pleural effusion on the chest X-ray](https://durgical.com/en/radiology/pleural-effusion-on-the-chest-x-ray/) - [Lines and tubes on the chest X-ray: where each tip should be](https://durgical.com/en/radiology/lines-and-tubes-on-the-chest-x-ray-where-each-tip-should-be/) - [A nodule or a mass on the chest X-ray](https://durgical.com/en/radiology/a-nodule-or-a-mass-on-the-chest-x-ray/) - [The child's chest X-ray: thymus, foreign body, croup and epiglottitis](https://durgical.com/en/radiology/the-child-s-chest-x-ray-thymus-foreign-body-croup-and-epiglottitis/) ## Related conditions 1 - [Atelectasis](https://durgical.com/en/conditions/atelectasis/) [← All of radiology](https://durgical.com/en/radiology/) Educational content; it does not replace a radiologist's report and is not a clinical instruction. Each study is ordered on the patient's assessment and your institution's protocols. Sources: [Atelectasis](https://www.ncbi.nlm.nih.gov/books/NBK545316/) (StatPearls (NCBI Bookshelf), 2024); [Chest and Mediastinal Imaging](https://www.ncbi.nlm.nih.gov/books/NBK559145/) (StatPearls (NCBI Bookshelf), 2026). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/radiology/lobar-collapse-on-the-chest-x-ray/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/radiology/lobar-collapse-on-the-chest-x-ray/