Deep sulcus sign
ChestRadiograph
An abnormally deep, lucent costophrenic sulcus extending inferolaterally on a supine chest radiograph.
What it means
A pneumothorax in the supine patient, where free pleural air collects anteriorly and basally.
Mechanism
In the supine position pleural air rises to the least dependent anterobasal recess, deepening and lucent-ising the lateral costophrenic angle.
Associated conditions
- Pneumothorax
- Trauma
- Barotrauma in ventilated patients
- Post-procedural (line or biopsy) air leak
Pearls
- It is a key clue to pneumothorax on supine films where the visceral pleural line may be hidden.
- In ICU patients an unexplained deep, lucent sulcus warrants an upright or decubitus film.
References
- Radiopaedia: Deep sulcus sign
For educational use only. This dictionary is a study aid and reference, not a diagnostic tool, and must not be used to guide clinical decisions or patient care. Imaging appearances vary; always correlate with the full clinical picture and confirm with a qualified radiologist.