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Table 1 Detailed descriptions of scanning sectors in LUS

From: Lung ultrasound—a primary survey of the acutely dyspneic patient

Chest

Sector

Boundaries

Anatomical/study significance

Anterior

R1 or LI (anterior upper)

Upper: clavicle; lower: 4th rib; medial: sternal edge; lateral: defined by LUS image of lung; beyond this border are contents of the axilla and clavipectoral triangle

• Horizontal fissure is in line with the 4th rib; therefore, this zone contains the upper lobe of the lung

R2 or L2 (anterior lower)

Upper: 4th rib; lower: variable, depending on body habitus and defined by curtain sign in LUS and appearance of abdominal contents;liver on the right side, bowel and spleen on the left; medial: sternal edge; lateral: anterior axillary line

• The 6th rib approximates the inferior most part of the lung and anterior insertion of diaphragm (not seen in normal LUS with curtain sign). Beyond the 6th rib is the potential space: costophrenic recess

• This sector contains mainly the middle lobe; on the left lung, lingular lobe; with a small portion of the lower lobe on the lateral side

• The sector on the left hemithorax is very small due to the position of the heart; no sector in cardiomegaly states

Rs or Ls supraclavicular fossa

Triangle formed by the clavicle, lower parts of sternomastoid and trapezius

• Optional study area for the following: first rib; apical pneumothorax; pulmonary tuberculosis

Lateral

R3 or L3 lateral axilla

Upper: axilla; lower: the axis of the 4th rib; anterior: anterior axillary line; posterior: posterior axillary line

• This sector contains primarily the upper lobe of the lung with a small portion of the lower lobe

R4 or L4 lateral lower

Upper: the axis of the 4th rib; lower: variable, depending on body habitus. Defined by curtain sign in LUS; anterior: anterior axillary line; posterior: posterior axillary line

• This sector contains primarily the lower lobe of the lung

Posterior

R5 or L5 posterior upper

Upper: defined by LUS image of the lung; medial: thoracic spine; lateral: medial border of scapula; lower: level of the inferior angle of the scapula

• This sector contains the upper lobe and lower lobe of the lung in almost equal proportion

R6 or L6 posterior lower

Upper: level of the inferior angle of the scapula; medial: thoracic spine

Lateral: posterior axillary line; lower: defined by curtain sign in LUS and appearance of abdominal contents ; liver on the right side; bowel and spleen on the left

• This sector contains primarily the lower lobe of the lung