Features of the PA Chest X-Ray

In order: trachea, carinus (point where the trachea splits), primary main bronchi/bronchus and secondary bronchi (two on left and three on right).

Left and right lungs.

• Lobes can only be seen when there is a pathology present.

What are the fibrous markings on the radiograph?

• Called lung markings

• Result from the radiopaque pulmonary (lung) arteries and veins

• Normal

• Purple: Hilar root or hilar zone.

1. Hilum: The opening on the lung.

2. Hilar root: The physical structures which pass through the hilum (i.e., the pulmonary vessels0.

3. Hilar zone: The area on the X-Ray where the shadow/silhouette of the hilar root is visible.

• Orange: Hilar point.

4. Hilar point: The point where the upper and lower pulmonary vessels

meet/converge at the lateral aspect (lateral face) of the lung.

• Left hilar point is usually HIGHER than the right hilar point since the left pulmonary artery ARCHES over the left main bronchus.

• Right hilar point is aligned at around T6/T7.

From left to right;

1. Right costophrenic angle

2. Right hemidiaphragm

3. Right cardiophrenic angle

4. Left cardiophrenic angle

5. Left hemidiaphragm

6. Left costophrenic angle

Clavicles

Sternum

• Harder to identify since it is superimposed by the vertebral column and the mediastinum.

In order:

1. Manubrium: Head of the sternum.

2. Body: Body of the sternum.

3. Xiphoid process: The lower part of the sternum.

Scapula

Posterior part of the rib

• Runs laterally and then curves inward.

One rib entirely

*NB: Costal cartilage is considered SEPARATE from the rib.

Red:

• Heart shadow, or the

• Cardiac silhouette

*NB: DO NOT call it the heart, SINCE you can not actually see the separate structures of the heart (you just see a radiopaque shadow).

• Aortic knuckle (or aortic knob or aortic loop): The rounded upper-part of the aortic silhouette — it is the shadow of the aortic arch.

• Parts of the aortic silhouette:

1. Aortic knob: Rounded upper part of the aortic silhouette.

2. Ascending aorta contour: The outline of the ascending aorta.

3. Descending aorta contour: The outline of the descending aorta.

Thymus

• Harder to see since it is superimposed by other structures such as the vertebrae and the trachea.

Oesophagus and stomach (cardia, fundus and pylorus).

Spleen

• Slightly radiolucent structure medial and slightly superior to the spleen is called the gastric bubble.

• Gastric bubble: A pocket of gas that is formed when air that is swallowed when you eat; normally found in the fundus.

Liver

• Reason why the hemidiaphragm sits more superior compared to the left hemidiaphragm since it pushes the right hemidiaphragm more up.

Breast tissue.

Anterior part of the rib.

• Image is slightly wrong since the rib does not connect all the way to the sternum; the costalcartilage exists between the sternum and the rib.