The chest x-ray shows the presence of pneumomediastinum. The heart is outlined by air and there is also a ‘tubular artery sign’ wherein the major neck vessel branches in the superior mediastinum are outlined by air.

The tubular artery sign is seen in pneumomediastinum when air in the mediastinum outlines the medial aspect of the major neck vessels and the air in the lung outlines the lateral aspect of the vessels.

The child was clinically stable and was managed conservatively and did well.

Reference: https://pubs.rsna.org/doi/full/10.1148/radiographics.20.4.g00jl131043