Part 3: Thoracic Cavity

Question 1

What are the divisions of the mediastinum?

Answer 1

Horizontal line passes from sternal angle (2nd rib) to T4. Above it lies superior mediastinum, below inferior mediastinum.
Inferior mediastinum divides into anterior, middles and posterior mediastinum. Anterior and posterior mediastinum are continuous with superior mediastinum

Question 2

The horizontal plane between sternal angle and T4 that divides mediastinum into superior and inferior also passes through what other important structures?

Answer 2

• Bifurcation of trachea
• Concavity of aortic arch
• Pulmonary trunk bifurcation is just inferior
• Azygous vein enters SVC
• Ligamentum arteriosum
  Superficial and deep parts of cardiac plexus

Question 3

What is the relation of pretracheal fascia with mediastinum?

Answer 3

Extends down from next and blends with pericardium

Question 4

What is the relation of prevertebral fascia with the mediastinum?

Answer 4

Extends down back of neck to blend with T4

Question 5

How is the pretracheal and prevertebral fascia important in regards to neck infections?

Answer 5

Neck infections in front of pretracheal fascia can drain into anterior mediastinum. Infections posterior to prevertebral will be trapped in superior mediastinum above C4. Infections else where can drain into posterior mediastinum