Figure 14.

posterolateral alveolar and/or pleural syndrome profile. (A) Pleural effusion (asterisk) in a 20-year-old female presenting with breathlessness and chest pain identified by visualizing the underlying visceral pleural line/“lung line” (arrow). “Quad sign,” a sonographic feature is depicted in the form of a rough quadrilateral bounded by the two ribs (R) with their posterior acoustic shadow on either side, the pleural line superiorly, and the lung line inferiorly. (B) M-mode tracing in a pleural effusion reveals a “sinusoidal” pattern. The underlying lung appears to be normal, with few Sub-B lines seen.