Radiographic anatomy of the thorax

Question 1

Why take thoracic radiographs

Answer 1

1. Respiratory disease
2. Trauma
3. Cardiovascular disease (particularly congestive heart failure)
4. Staging of neoplasia

Question 2

Why take multiple views

Answer 2

1. 2d image of 3d structure

2. to get accurate representation of structures in thorax - those closer to the plate = larger

Question 3

When taking radiographic anatomy of thorax what views?

Answer 3

1. left lateral
2. right lateral
3. either ventrodorsal (on back) or dorsoventral

Question 4

if take radiograph of lungs what position and why

Answer 4

1. ventrodorsal as lungs sit dorsally and laterally to heart

Question 5

what position for heart

Answer 5

1. dorsal ventral as heart is ventral to lungs = close to plate

Question 6

What is an X-ray

Answer 6

short wave electromagnetic radiation

Question 7

Where is the scapula on a lateral thoracic radiograph?

Answer 7

Around about in line with base of heart

Question 8

Why does the diaphragm appear solid?

Answer 8

D overlying liver and GI that is behind it

Question 9

Lateral thoracic radiograph with letter R means

Answer 9

Right lateral recumbancy

Question 10

If right lateral recumbency which lung is better represented?

Answer 10

Left as full of air, right is collapsed even if closer to plate

Question 11

What are we seeing when we look at the heart

Answer 11

cardiac silhouette - pericardium and heart

Question 12

when do you knwo if enlarged cardiac silhouette and what does it indicate

Answer 12

1. 2/3rds of depth of thorax
2. 3 rib spaces
3. Trachea not parallel to sternum but pushed up
4. fluid in pericardium

Question 13

black tube

Answer 13

black = air = trachea

Question 14

what si the large greyish tube that looks like it is leaving the CS and going towards Diaphragm

Answer 14

Caudal vena cava

Question 15

On right lateral recumbancy what positioning is the heart in?

Answer 15

1. Cranial vena cava = horizontally into base (harder to see)
2. Caudal VC = horizontally, in line with cranial VC, out of heart towards diaphragm
3. Aorta = structure at top curving up and back towards caudal thoracic vertebrae
4. LHS of heart is towards right
5. Left ventricle = bottom and closest to diaphragm
6. Left auricle above LV
7. bottom LHS = RV, directly above = feeds into pulmonary trunk
8. Right auricle = just below start of aorta, most base of heart

Question 16

What is the positioning of the heart on a DV/VD

Answer 16

Think of it as a clock face

1. Cranial and caudal VC = branches coming out of top and bottom (slightly to side)
2. 12/1 o’clock = aorta arch
3. 1/2 o’clock = pulmonary artery
4. 3 o’clock = left auricle
5. 4 and 5 o’clock = LV
6. 6-8 o’clock = RV
7. 9-10 o’clock = Right auricle

Question 17

What are right/left auricles/ appendages?

Answer 17

right = attached to the heart's right atrium. It's a small, cone-shaped pouch which comes out from the upper and front part of the atrium and overlaps the root of the aorta
left = small, muscular pouch at the upper corner of the left atrium. It collects oxygenated blood as it leaves the lungs and moves the blood into the left ventricle

Question 18

What do you see with left atrial enlargement?

Answer 18

The trachea looks like its jumping over something at the end

Question 19

What would grey lungs indicate

Answer 19

fluid build up: pulmonary oedema

Question 20

What about the lungs on a radiograph

Answer 20

Shouldn’t be able to distinguish the lobes- if can see = something abnormal = air (black) or fluid (grey)
1. bright outline = fluid in pleural cavity = pleural effusion = can’t inflate lungs

Question 21

What are the lobes of the lung

Answer 21

RHS:
1. cranial, middle, caudal, accessory
LHS:
1. cranial (subdivided into cranial and caudal)
2. Caudal

Question 22

What is one way to identify if LHS or RHS on dorsal ventral/ VD?

Answer 22

1. media stinum joins diaphragm slightly left of midline
2. apex of heart, slightly left
3. caudal vena cava on RHS to diaphragm

Question 23

Where should the apex of the heart be

Answer 23

1. touching sternum

2. close to diaphragm

Question 24

sharp heart outline indicates what

Answer 24

pericardium effusion = free fluid in peri = need to ultrasound