Seashore sign is another eFAST finding usually in the lungs in the M-mode that depicts the glandular echogenicity of the lung abutted by the linear appearance of the visceral pleura. This sign is a normal finding.
The "seashore sign" is a common finding on eFAST imaging of the lungs in M-mode, where it shows glandular echogenicity (how sound waves reflect off tissues) and a linear appearance of the visceral pleura. It's typically a normal observation.