First rib; count down from here for diaphragmatic level
Peripheral 1-2 cm of lung fields have no markings except
The minor fissure
Top of the diaphragm is near the medial half of its length. The top of the right diaphragm is normally at a level between the anterior end of the anterior 6th rib and the anterior 7th rib. The level of the diaphragm can also be reported eith reference to the posterior ribs: on full inspiration, the domes of the diaphragm are seen overlying the posterior aspects fot he 10th and 11th ribs.
Left diaphragm is lower in 90-95% of normals by roughly half an interspace (2% greater than 3 cm)
Inferior margins of the posterior ribs are often ill-defined
Anterior mediastinal line (apposed visceral and parietal pleura of the two upper lobes
Superior vena cava shadow blends imperceptibly into the shadows of the neck
Region of the azygous vein (vein not visible). A caliber greater than 7 mm is suggestive of raised venous pressure, or enlargement of adjacent node. Normal may be up to 10 mm.
Right descending pulmonary artery. Not greater than 16 mm in men, 15 mm in women
Pulmonary arteries and veins. Hard to distinguish the two. Arteries are vertical and medial and emerge from the hilum. Veins are horizontal and lateral ad run toward the left atrium below the hilum.
Border of the right atrium
Inferior vena cava
Aortic arch
Left pulmonary artery
Border of the left ventricle
Descending aorta
Fat density lines in the intermuscular fascial layers
