The chest x- ray shows Naclerio’s V sign, a radiological feature of pneumomediastinum.

There is air outlining the descending thoracic aorta and the medial left hemi-diaphragm in a V shaped manner.

Naclerio, a thoracic surgeon from New York, first reported this sign in patients with spontaneous oesophageal rupture. However, this sign is also seen in pneumomediastinum due to other causes.

The above patient went onto have a CT scan which revealed a distal oesophageal rupture (Boerhaave syndrome).

Further reading/Reference: https://pubs.rsna.org/doi/abs/10.1148/radiol.2451042197?journalCode=radiology