1. Small Animal Thorax
Lavin: Chapter 19

2. Objectives: Thorax
Correctly & safely position a dog or cat for various thoracic views
Be able to describe common and alternate thoracic views
ID normal thoracic radiographic anatomy

3. Skeletal Anatomy Review

4. Thoracic Viscera: Anatomy Review

5. Small Animal Thorax: Considerations
Indications for radiography:
Normal views:
Lung disease - VD, both left & right lateral
Cardiac – DV, right OR left lateral
Metastasis – VD or DV, both left & right lateral
“Met check”
Oblique views may be necessary

6. Thorax Views: Patient Prep
Clean, dry fur
No matted hair
Remove collars and leashes
Place in correct position on the
table (Heel effect)
Measure in the position they are
to be radiographed in
Thickest part is usually caudal
aspect of scapula

7. Small Animal Thorax: Radiographic Concerns
Settings:
kVp: ______________ mA: ______ mAs: ______
Use highest mA and shortest time for mAs
Mass or fluids suspected?
May need to increase initial kVp by 10-15%
Entire lung field must be included for film to be diagnostic
___________ __________ to
May need to take two films to include all anatomy

8. Small Animal Thorax: Radiographic Concerns
Expose at peak _______________
Maximizes air in lung fields
Separates heart and diaphragm
Can be synchronized with PPV if intubated
Control panting!
Blow in face, hold mouth shut
Exception: Vet may request on expiration when looking for fluid or air in the plural space

9. Lateral Thorax: Considerations
Entire ribcage should be included
Place markers at ventral aspect
Pull forelimbs as far cranially as possible
Do not allow rotation!
All anatomy parallel to cassette
If lung lesions are suspected:
best seen when placed
___________ from
Image receptor.

10. Lateral Thorax: Considerations
Collimation:
Cranial margin- scapulohumeral articulation (_________ _________)
Caudal margin- first __________ vertrbral body
This places central beam directly over the heart
Look for superimposition!
*Normal sized heart =
times width of
______________ space

11. Confirming Central Line Placement

12. Metastasis

13. Pleural Effusion

14. Pulmonary Edema

15. Dorsoventral Thorax: Considerations
DV is best view for:
Heart
Pulmonary arteries/veins
Center directly over heart
Include cranially from shoulder joint, caudally to diaphragm
Pull forelimbs cranial and try to rotate paws inward
Ensure patient is straight with no rotation!
Symmetry!

16. Heartworm Disease
“D” shaped heart

17. Ventrodorsal Thorax: Considerations
Best for:
Lungs
Mediastinum
Measure over the caudal border of the scapula
Difficult view in dyspneic patients
Symmetry!

18. Pneumothorax

19. Metastatic Lungs

20. Other Thorax Views Lateral decubitus DV decubitus
Standing lateral view
Used when looking for fluid-gas margins or traditional views cannot be tolerated

21. Thoracic Anatomy: Review
Four anatomic regions of the thorax:
Extrathoracic
Skeleton and diaphragm
Pleural space
Contains lungs
Separates lungs from body wall
Contains small amount of fluid not visible on radiograph
Pulmonary parenchyma
Lung lobes, bronchi, bronchioles, alveoli

22. Thoracic Anatomy: Review
Mediastinum
The space between the lungs
Contains the trachea, esophagus, heart, aorta, and various nodes, ducts, and nerves
“Cardiac silhouette”
Divides thorax into right & left sides

23. Other Thoracic Structures
Esophagus
Usually not noted on radiographs
Unless highlighted by feeding tube, food, or is enlarged
Trachea –
Air-filled
Usually ___________ to esophagus
Towards right on lateral

24. Small Animal Thorax

25. Small Animal Thorax