Ch.2 - Recognizing Normal Chest Anatomy

Question 1

Bronchi in CXR are?

Answer 1

Invisible - Very thin-walled + contain air + surrounded by air.

Question 2

Why look at the LATERAL chest?

Answer 2

1. It can help determine the location of disease you already identified as being present on the frontal image.
2. It can confirm the presence of disease you may be unsure of on the basis of the frontal image alone, such as a mass or pneumonia.
3. It can demonstrate disease not visible on the frontal image.

Question 3

What do we see normally in the retrosternal clear space?

Answer 3

A relatively lucent crescent is present just behind the sternum + anterior to the shadow of the ascending aorta.

Question 4

The retrosternal clear space - Look for what?

Answer 4

For this clear space to FILL-IN with SOFT-TISSUE density when an anterior mediastinal mass is present.

Question 5

The retrosternal clear space - Pitfall?

Answer 5

Patient’s superimposed arms - NOT A SOFT TISSUE.
Although patients are asked to hold their arms over their head for a lateral CXR, many are too weak to raise their arms.
–> Solution: Identify the humerus.

Question 6

Frontal or lateral view for the hilar region?

Answer 6

Difficult to assess on the frontal view –> Especially when enlarged.
Comparison with the opposite normal side is IMPOSSIBLE.
LATERAL VIEW MAY HELP.

Question 7

Most of the hilar densities are made up of?

Answer 7

The PULMONARY ARTERIES.

Question 8

When there is a HILAR MASS, such as might occur with enlargement of hilar lymph nodes …?

Answer 8

The HILUM will cast a distinct, lobulated masslike shadow on the lateral radiograph.

Question 9

Major and minor fissures on the lateral film?

Answer 9

May be VISIBLE as fine, white lines.

Question 10

The course of the MAJOR fissure?

Answer 10

Obliquely, roughly from the level of the 5th thoracic vertebra to a point of the diaphragmatic surface of the pleura a few cm BEHIND THE STERNUM.

Question 11

The MINOR fissure lies?

Answer 11

At the level of the 4th anterior rib (on the right side only) and is HORIZONTALLY oriented.

Question 12

Only which fissure is usually visible on the … view?

Answer 12

FRONTAL.

Question 13

Thickening of the fissure by fluid is almost always associated with?

Answer 13

Other signs of FLUID in the chest such as:

1. Kerley B lines.
2. Pleural effusions.

Question 14

Thickening of the fissure by FIBROSIS is the most likely cause if?

Answer 14

THERE ARE NO OTHER SIGNS OF FLUID IN THE CHEST.

Question 15

Virtually all the white lines seen in CXR are?

Answer 15

BLOOD VESSELS

Question 16

How to tell the RIGHT from the LEFT hemidiaphragm on the lateral radiograph?

Answer 16

1. RIGHT –> Visible for its entire length from front to back.
2. RIGHT –> Higher than the left.
3. LEFT is seen sharply posteriorly BUT i silhouetted by the HEART MUSCLE anteriorly.
4. AIR in the stomach or splenic flexure appears immediately below the LEFT diaphragm.

Question 17

What happens NORMALLY to the thoracic spine as you view it from neck to diaphragm?

Answer 17

It appears to get BLACKER because there is LESS DENSE TISSUE for the x-ray beam to traverse just above the diaphragm than in the region of the shoulder girdle.

Question 18

What is the spine sign?

Answer 18

A left lower lobe pneumonia SUPERIMPOSED on the lower spine in the LATERAL VIEW makes the spine appear WHITER (more dense) just above the diaphragm –> Spine sign.

Question 19

What is the MCC of obscure retrosternal space?

Answer 19

Adenopathy.

Question 20

It takes about … cc to blunt the POSTERIOR costophrenic angle on the lateral film, while it takes … cc to blunt the LATERAL costophrenic angles on the frontal film.

Answer 20

75 cc.

250-300 cc.

Question 21

Retrosternal clear space - What you should see?

Answer 21

Lucent crescent between sternum + ascending aorta.

Question 22

Hilar region - What you should see?

Answer 22

No discrete mass present.

Question 23

Fissures - What you should see?

Answer 23

Major and minor fissures should be pencil-point thin, if visible at all.

Question 24

Thoracic spine - What you should see?

Answer 24

1. Rectangular vertebral bodies with parallel end plates.

2. Disk spaces maintain height from top to bottom of thoracic spine.

Question 25

Diaphragm and posterior costophrenic sulci - What you should see?

Answer 25

1. Right hemidiaphragm slightly higher than left.

2. Sharp posterior costophrenic sulci.

Question 26

5 technical factors that will help you determine if a chest radiograph is ADEQUATE for interpretation or whether certain artifacts may have been introduced that can lead you astray:

Answer 26

1. Penetration.
2. Inspiration.
3. Rotation.
4. Magnification.
5. Angulation.
   - PIRMA -

Question 27

To determine if a frontal CXR is ADEQUATELY PENETRATED, you should be able to see?

Answer 27

The thoracic spine through the heart shadow.

Question 28

UNDERPENETRATION can introduce at least 2 errors into your interpretation:

Answer 28

1. The left hemidiaphragm may NOT be visible on the frontal film because the LEFT LUNG BASE may appear opaque (white) –> Look at the LATERAL CXR.
2. The pulm. markings (mostly blood vessels) may appear more prominent than they really are. Mistakenly think the patient is in CHF or has pulm. fibrosis –> Look for OTHER SIGNS of CHF + Look at the LATERAL CXR.

Question 29

What is the pitfall of OVERpenetration?

Answer 29

TOO DARK - The lung marking may seem decreased or absent –> You could mistakenly think that the patient has emphysema or a pneumothorax or, if the degree of overpenetration is marked, it could render findings like a pulmonary nodule almost invisible.

Question 30

Solution for overpenetration?

Answer 30

Look for other radiographic signs of EMPHYSEMA or PNEUMOTHORAX.

Question 31

The degree of inspiration can be assessed by counting?

Answer 31

The NUMBER of POSTERIOR ribs visible above the diaphragm on the frontal chest radiograph.

Question 32

Pitfall of POOR inspiration?

Answer 32

May lead you to mistakenly think the study shows LOWER LOBE pneumonia –> Look at the LATERAL CXR to confirm the presence of pneumonia.

Question 33

Significant rotation may?

Answer 33

Alter the expected contours of the heart + great vessels, the hila, and hemidiaphragms.

Question 34

The easiest way to assess whether the patient is rotated toward the left or right is by studying?

Answer 34

The position of the MEDIAL ENDS of each clavicle relative to the spinous process of the THORACIC VERTEBRAL BODY between the clavicles.

Question 35

In AP or PA CXR is the heart slightly magnified?

Answer 35

AP

Question 36

What do we see on APICAL LORDOTIC VIEWS?

Answer 36

Anterior structures in the chest (like the clavicles) are projected HIGHER on the resultant radiographic image than POSTERIOR STRUCTURES in the chest, which are projected lower.

Question 37

Penetration - What you should see?

Answer 37

The spine should be visible through the heart.

Question 38

Inspiration - What you should see?

Answer 38

At least 8 to 9 POSTERIOR ribs should be visible.

Question 39

Rotation - What you should see?

Answer 39

Spinous process should fall equidistant between the medial ends of the clavicles.

Question 40

Magnification - What you should see?

Answer 40

AP films (mostly portable CXR) will magnify the heart slightly.

Question 41

Angulation - What you should see?

Answer 41

Clavicle normally has an “S” shape and superimposes on the 3rd or 4th rib.