Sail sign of the chest
Differential diagnosisleft lower lobe collapse

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]


  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.
  3. ^ "Pneumomediastinum Revisited" July 2000 RadioGraphics, 20, 1043-1057