1. ANATOMY OF
MEDIASTINUM
Dr Nikrish S Hegde

2. MEDIASTINUM
Middle space
In the thoracic cavity
Between the lungs

3. DIVISIONS
Divided into compartments
Why?
1) Aid in localization of lesion.
2) Aid in the differential diagnosis.

4. Superior
Inferior
Anterior
2) Middle
3) Posterior
1)

5. SUPERIOR MEDIASTINUM
Anteriorly: Manubrium sterni
Posteriorly: Upper 4 thoracic
vertebrae
Superiorly : Plane of thoracic inlet
Inferiorly : An imaginary line
passing through the sternal angle
and lower border of 4th thoracic
vertebrae.

8. INFERIOR MEDIASTINUM
Anterior
Middle
Posterior

9. ANTERIOR MEDIASTINUM
Thymus,
Internal
mammary
Artery,
Lymph
Nodes,
Fat

10. MIDDLE MEDIASTINUM
Heart ,Aorta,
Brachiocephali
c artery,
SVC,IVC,
Azygos,
Hemiazygos,
Phrenic ,
Vagus
Trachea ,
Lymph nodes

11. POSTERIOR MIDIASTINUM
Lymph
Nodes,
Fat ,
Vertebral
Column
& Nerves

13. CT – BRIEF OVERVIEW
 Localization
 Extent
 Characterise
 Shortening of scanning time
 Limit the total dose of contrast
CT is usually used to further evaluate an
abnormality detected on Chest radiograph.

14. NON CONTRAST - CT
Scan time is less.
No contrast reaction.
Cost is lower.
Takes longer time to interpret.

15. CONTRAST ENHANCED CT
2 ml – 4ml/sec
Total 150 ml
Large bore iv catheter18-20 gauge
Time of the bolus in relation to the scan varies.

16. CT scans of the mediastinum are
reconstructed, filmed and interpreted in an
axial format.
Continuous data can be acquired in a single
breath hold and therefore excellent 2D and 3D
reconstruction of images is done.

17. AXIAL PLANE.

18. THORACIC INLET

19. LEFT BRACHIOCEPHALIC VEIN

20. AORTIC ARCH

21. AZYGOS VEIN

22. AORTO-PULMONARY WINDOW

23. LEFT PULMONARY ARTERY

24. RIGHT PULMONARY ARTERY

25. LEFT ATRIAL

26. 4 CHAMBER

28. 3 CHAMBER

29. CORONAL PLANE.

30. AORTIC OUTFLOW TRACT

32. PULMONARY ARTERY

33. LEFT ATRIAL

34. DESCENDING AORTA

35. SAGITTAL PLANE.

36. SVC

37. RIGHT ATRIAL LEVEL

38. AORTIC OUTFLOW TRACT

39. PULMONARY OUTFLOW TRACT

40. LYMPH NODES

41. SUPRACLAVICULAR & UPPER
PARATRACHEAL

42. PREVERTEBRAL & PREVASCULAR

43. LOWER PARATRACHEAL

44. SUBAORTIC & PARA AORTIC

45. CARINAL, PARAOESOPHAGEAL &
HILAR