Pleural friction

Pleural friction is the fibrin exudation deposited in the viscera and parietal pleura during pleural inflammation, which makes the surface of the pleura rough, and the two layers of pleura rub against each other during breathing, and feel like leather rubbing during palpation. The signs are most clear at the axillary midline and lower armpit of the affected side. When pleural effusion occurs, the two layers of pleura separate and the pleural friction disappears. The friction sensation can reappear during the effusion absorption.