Level of the lower border of the lung at the mid-axillary line is -

The inferior margin of pleura extends onto diaphragm at the level of (Costodiaphragmatic line) -        8th rib in the midclavicular line -        10th rib in mid-axillary line -        12th rib at the lateral border of erector spinae. The lower border of lungs extends till the level of -        6th rib in the midclavicular line -        8th rib in mid-axillary line -        10th rib at the lateral border of erector spinae.