Fig. 5.

Surface anatomy of the regions of the lung. Ultrasound surface anatomy: the parasternal, anterior axillary and posterior axillary lines divide the chest wall into anterior, lateral and posterior regions. a The anterior region, delineated superiorly by the clavicle, inferiorly by the liver or the spleen, medially by parasternal line and laterally by the anterior axillary line. The anterior region is further divided by an arbitrary line to anterior upper zone and anterior lower zone. b The lateral region, delineated superiorly by the axilla, inferiorly by the liver or the spleen, anteriorly by the anterior axillary line and posteriorly by the posterior axillary line. An arbitrary line further divides the lateral region to lateral upper zone and lateral lower zone. c The posterior region, delineated by the posterior axillary line laterally and paravertebral line medially. A horizontal arbitrary line at the tip of the scapula further divides the posterior region to upper and lower zone. ALZ anterior lower zone, AUZ anterior upper zone, L lingula, LLL left lower lobe, LLZ left lower zone, LUL left upper lobe, PLZ posterior lower zone, PUZ posterior upper zone, RLL right lower lobe, RML right middle lobe, RUL right upper lobe