Chest, Ribs, Sternum and Airway

Landmarks and Habitus

Chest positioning starts with landmarks. The vertebra prominens (C7) is the posterior starting point, the jugular notch lies at T2-T3, the sternal angle at T4-T5 marks the carina, and the xiphoid tip lies at about T9-T10. The chest central ray (CR) is usually T7, found 7 to 8 inches (18 to 20 cm) below the vertebra prominens or 3 to 4 inches (8 to 10 cm) below the jugular notch. A hypersthenic patient has a broad, shallow chest with a high diaphragm, so the digital detector goes crosswise to include both costophrenic angles; an asthenic patient has a long, narrow chest, so the detector stays lengthwise.