veins

What are the anterior intercostal veins formed by?

Venae comitantes of the internal thoracic artery.

Where do the 7th, 8th, and 9th anterior intercostal veins end?

In the musculophrenic vein.

What is formed by the union of the superior epigastric vein and the musculophrenic vein?

Internal thoracic vein.

What is the origin of the azygos vein?

Union of the right subcostal vein and the right ascending lumbar vein at T12.

Where does the azygos vein drain?

Into the back of the superior vena cava.

Which veins cross the midline from left to right to enter the azygos vein?

Both hemiazygos veins.

What does the superior hemiazygos vein collect from?

5th to 8th left posterior intercostal veins and left bronchial veins.

What is the classification of intercostal nerves?

Typical (T3 to T6) and Atypical (T1 and T7 to T12).

What does T12 nerve supply?

Only the anterior abdominal wall.

Why are stab wounds through the posterior parts of intercostal spaces more dangerous?

Because intercostal nerves in the posterior part run in the middle of the space.

Where is the safe site for needle puncture in the intercostal spaces?

In the lateral parts to avoid injury to posterior intercostal nerves and vessels.