Sail sign of the chest

Sail sign of the chest
Sail sign of the chest
Differential diagnosis	left lower lobe collapse

Last updated August 12, 2025

On a chest X-ray, the sail sign is a radiologic sign that suggests left lower lobe collapse.^[1] In children, however, a sail sign could be normal, reflecting the shadow of the thymus.^[2]

The thymic sail sign or spinnaker-sail sign is due to elevation of the thymic lobes in the setting of pneumomediastinum.^[3]

References

↑ Bejvan S, Godwin J (1996). "Pneumomediastinum: old signs and new signs". AJR Am J Roentgenol. 166 (5): 1041–8. doi:10.2214/ajr.166.5.8615238. PMID 8615238.
↑ "THYMIC SAIL SIGN". www.mypacs.net.
↑ Zylak, Christopher M.; Standen, James R. (July 2000). "Pneumomediastinum Revisited". RadioGraphics. 20 (4): 1043–1057. doi:10.1148/radiographics.20.4.g00jl131043. ISSN 0271-5333.

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[1] Bejvan S, Godwin J (1996). "Pneumomediastinum: old signs and new signs". AJR Am J Roentgenol. 166 (5): 1041–8. doi:10.2214/ajr.166.5.8615238. PMID 8615238.

[2] "THYMIC SAIL SIGN". www.mypacs.net.

[3] Zylak, Christopher M.; Standen, James R. (July 2000). "Pneumomediastinum Revisited". RadioGraphics. 20 (4): 1043–1057. doi:10.1148/radiographics.20.4.g00jl131043. ISSN 0271-5333.

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