The sinusoid sign in lung ultrasound refers to the dynamic, undulating appearance of the pleural line, often seen during inspiration and expiration in healthy lungs. This subtle, wave-like motion reflects the normal sliding of the visceral and parietal pleura, indicating the absence of pneumothorax or significant pleural adhesions. Recognizing the sinusoid sign is a key diagnostic feature for ruling out conditions that impede lung sliding.
This ultrasound finding is critical for medical professionals evaluating lung pathology, particularly in emergency and critical care settings. It helps differentiate normal lung mechanics from abnormalities, making it an essential component of pulmonary ultrasound assessment and aiding in accurate and timely diagnoses.