Thoracic 1 Flashcards
How can you differentiate the L and R ribs on a lateral chest X-ray?
Left ribs are smaller with sharper edges
Note: Lateral CXRs are taken in the left lateral position, meaning the left ribs are against the detector.
How can you differentiate L and R diaphragms on a lateral CXR?
- Left has stomach bubble under
- Left is not seen anteriorly (due to heart)
- Left is lower
What structure appears as “the dark hole” on a lateral CXR?
The left upper lobe bronchus (en face)
How can you differentiate the L and R main pulmonary arteries on a lateral CXR?
L pulmonary artery is posterior to “the dark hole” (en face bronchus)
R pa is anterior (and also more inferior)
Note: “L”osers to the back.
Retrotracheal triangle
Dark triangle behind the trachea on the lateral CXR (above the aortic arch and anterior to the spine)
Note: This should always be black.
Common reason for an opacified retrotracheal triangle
Aberrant right subclavian artery
Note: The retrotracheal triangle is the (usually) dark triangle behind the trachea on the lateral CXR (above the aortic arch and anterior to the spine).
Which “hilar point” should be superior?
The left hilar point should be ~1 cm above the right hilarity point on CXR
Note: The hilar point is the medially oriented “V” at the hill: > <
On lateral CXR, which major fissure is anterior?
The right major fissure is anterior to the left
How many layers of pleura make up an azygos lobe fissure?
4 (2 visceral and 2 parietal)
How many bronchopulmonary segments are there on the right?
10 (3 upper, 2 middle, and 5 lower)
How many bronchopulmonary segments are there on the left?
8 (4 upper and 4 lower)
What are the bronchopulmonary segments on the right?
- R upper (apical, posterior, anterior)
- R middle (medial and lateral)
- R lower (superior, anterior, posterior, medial, and lateral)
What are the bronchopulmonary segments on the left?
- L upper (apicoposterior, anterior, superior singular, and inferior lingular)
- L lower (superior, anteromedial, lateral, posterior)
Pig bronchus
AKA tracheal bronchus, a normal variant where the right upper lobe bronchus originates directly from the trachea
Note: May cause recurrent RUL pneumonia.
Cardiac bronchus
An accessory bronchus that originates from the right bronchus intermedius
Note: It is usually blind ending, but may cause recurrent infections.
What separates the superior mediastinum from the rest of the mediastinum?
A plane at the level of the sternomanubrial junction (also at the level of T4)
What is the posterior border of the anterior mediastinal space?
Pericardium
What is in the middle mediastinum?
- The heart
- Roots of central vessels (e.g. aorta)
- Tracheal bifurcation
- Phrenic nerves
What are the borders of the posterior mediastinum?
- Posterior pericardium
- Spine (anterior longitudinal ligament)
Note: Contains the esophagus, lower thoracic duct, and descending aorta.
What is the most anterior structure in the superior mediastinum?
The thymus
What is the normal number of pulmonary veins?
4
- R superior
- R inferior
- L superior
- L inferior
Note: This is highly variable.
Supernumerary pulmonary veins predispose to…
Atrial fibrillation
What is the most common supernumerary vein?
Right middle
What is the most common vein sleeve to cause atrial fibrillation?
Left superior pulmonary vein