chest x-ray anatomy

Question 1

what are the main things to look at in a chest x ray? (11 things)

Answer 1

trachea and bronchi
hilar structures
lung zones
pleura
lung lobes and fissures
costophrenic angles 
diaphragm
heart 
mediastinum
soft tissues
bones

Question 2

name all the parts of the x ray shown in the picture

https://www.radiologymasterclass.co.uk/tutorials/chest/chest_home_anatomy/chest_anatomy_start#top_1st_img

Answer 2

1-trachea
2-hilum/hila
3-lungs
4-diaphragm
5-heart
6-aortic knuckle/knob (refers to the frontal chest x-ray appearance of the distal aortic arch)
7-ribs
8-scapulae
9-breasts
10-bowel gas

note: obscured/invisible structures (might only become visible when ABNORMAL):
- sternum
- esophagus
- spine
- pleura
- fissures
- aorta

Question 3

hehe just learn bout the normal trachea and major bronchi in this picture

https://www.radiologymasterclass.co.uk/tutorials/chest/chest_home_anatomy/chest_anatomy_page1#top_1st_img

Answer 3

note: trachea should be CENTRAL/slightly to the right at the level of the aortic knuckle/knob
* if trachea is deviated, decide if it has been pushed or pulled, and if so, by which disease process (e.g. tension pneumothorax would cause trachea to be pushed towards other side)

Question 4

what does each hilum contain?

https://www.radiologymasterclass.co.uk/tutorials/chest/chest_home_anatomy/chest_anatomy_page2#top_2nd_img

Answer 4

• one main bronchus
• one pulmonary artery
• two pulmonary veins (superior-inferior)
• also nerves & lymphatics

note: *right pulmonary artery passes ANTERIOR to right main bronchus & left pulmonary artery passes POSTERIORLY over left main bronchus
* left hilum is usually HIGHER than right

Question 5

what is the purpose of comparing lung zones (NOT LOBES!!)?

Answer 5

in order to observe for any abnormalities when comparing both sides of the lungs

note: however, some pathologies can result in bilateral lung abnormalities, which make comparison of left with right difficult
https: //www.radiologymasterclass.co.uk/tutorials/chest/chest_home_anatomy/chest_anatomy_page3#top_1st_img

Question 6

what do normal pleura and pleural spaces look like on an x ray?

Answer 6

not visible

note: if they are clearly visible, it might be due to disease e.g. mesothelioma (pleural thickening) or pleural effusion or pneumothorax etc.

Question 7

what can be observed on an x ray of the left lung?

Answer 7

oblique fissure (MAY be seen on lateral x ray)

https://www.radiologymasterclass.co.uk/tutorials/chest/chest_home_anatomy/chest_anatomy_page5

Question 8

what can be observed on an x ray of the right lung?

Answer 8

horizontal fissure (frontal/lateral x ray)

oblique fissure (MAY be seen on lateral x ray)

https://www.radiologymasterclass.co.uk/tutorials/chest/chest_home_anatomy/chest_anatomy_page5

Question 9

what accessory fissure is commonly observed on a chest x ray (1-2% of individuals)?

Answer 9

azygos fissure

https://www.radiologymasterclass.co.uk/tutorials/chest/chest_home_anatomy/chest_anatomy_page5#top_5th_img

Question 10

which hemidiaphragm is usually higher than the other?

Answer 10

right one is usually higher because the liver is located directly below it

note: *contours of hemidiaphragms do NOT demarcate bottom of the lungs as they actually descend into posterior side
https: //www.radiologymasterclass.co.uk/tutorials/chest/chest_home_anatomy/chest_anatomy_page7

Question 11

what to look for when assessing the diaphragm on an x ray?

Answer 11

inferior displacement of diaphragm = lung hyperexpansion

raised position of a single hemidiaphragm = MAY be phrenic nerve palsy (https://radiopaedia.org/articles/phrenic-nerve-palsy#nav_radiographic-features)

Question 12

what are the costophrenic recesses/angles?

Answer 12

points at which chest wall and diaphragm meet

note: *should be SHARP on an x ray
https: //www.radiologymasterclass.co.uk/tutorials/chest/chest_home_anatomy/chest_anatomy_page6

Question 13

what do you assess for at the costophrenic angle?

Answer 13

blunting = often due to presence of pleural effusion or other pleural/lung diseases (e.g. lung hyperexpansion)

Question 14

what does the cardiothoraic ratio refer to?

Answer 14

cardiothoracic ratio = cardiac width:thoracic width (usually expressed as a percentage)

note: assuming x ray is PA view and cardiac size is not exaggerated by external factors

Question 15

what is the normal cardiothoracic ratio?

Answer 15

about 1:2 or 50% and below

note: anything greater than this is abnormal, about more than or equal to 0.55

Question 16

what are heart contours on an x ray?

Answer 16

https://www.radiologymasterclass.co.uk/tutorials/chest/chest_home_anatomy/chest_anatomy_page8#top_2nd_img

Question 17

what does it mean when heart contours are not clearly seen on an x ray?

Answer 17

MAY indicate increase in density of adjacent lung

note: e.g. if lingula of the upper lobe of left lung is affected by lobar pneumonia, left heart border may not be seen OR right middle lobe pneumonia may also cause right heart border to not be seen

Question 18

what do you have to look out for in terms of soft tissues on an x ray?

Answer 18

• obesity may obscure underlying structures e.g. lung markings
• breast asymmetry (density differences on both sides) may be confused for underlying disease
• large breasts may obscure costophrenic angles
• nipple shadows may be mistaken for lung nodules

https://www.radiologymasterclass.co.uk/tutorials/chest/chest_home_anatomy/chest_anatomy_page10

Question 19

what are the bones visible on a chest x ray?

Answer 19

clavicles
(anterior end of 5-7) ribs
scapulae
spine
proximal humeri (upper arms)
sternum (usually obscured)

Question 20

what should you look out for in the bones on a chest x ray?

Answer 20

metastases

less than 5 ribs seen = incomplete inspiration

more than 7 ribs seen = lung hyperexpansion

note: chest x ray usually not helpful for acute rib fractures unless you’re looking for additional complications, CT scan better for rib fractures