4.8: Pleura

See written notes

Pleura

Pleura investing lung root hangs down to form pilmonary ligament; this provides dead space for root to enter when it descends in deep inspiration, and for vascular expansion.

Innervation

Parietal pleura by intercostal nerves; diaphragmatic pleura by phrenic nerve over dome, intercostal nerves at periphery. Mediastinal pleura by phrenic nerve.

Visceral pleura is insensate.

Surface markings

Parietal pleura projects over medial ¹/₃ of clavicle for 3cm.

A point is noted at each of even-numbered ribs:

2^nd	Pleurae from each side meet anteriorly, then pass vertically down behind sternum
4^th	Pleurae then diverge; L descends laterally ½way to apex of heart
6^th	Both pleurae turn laterally
8^th	Pleurae cross mid-clavicular lines
10^th	Pleurae cross mid-axillary lines
12^th	Cross rib at lateral border of erector spinae

From 12^th rib pleura runs medially to lower border of 12^th vertebra \triangle of pleura exists below the 12^th rib.