PHYS 799 Lecture Notes - Lecture 16: Mediastinum, Pleural Cavity, Lipoma
23 Apr 2019
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If upright, stomach will have horizontal fluid level. A low volume film can make lower lobe vessels look dense, heart look wider. Cxr is always oriented as if patient is facing you (r side of body, l side of image) Lung volume count anterior ribs (run diagonally, posterior ribs run horizontally); r hemidiaphragm should be around 6th rib. Rotation distance from spinous process to medial end of clavicle should be same on both sides rotate to r side, distance increases on r side, anterior mediastinum (heart) moves r, posterior mediastinum moves l. Projection posteroanterior (pa) or anteroposterior (ap); heart appears larger on ap film. In pa films, hands on hips, scapula moves out of way; in ap film, stand at attention. Position gravity affects position of pleural fluid. Silhouette sign when 2 structures of same radiographic density physically touch, margin between them is lost on x-ray (conversely, if 2 structures of different density touch, margin appears)
