Intercostal space, muscles and nerves

Question 1

What are the intercostal muscles called, list from most superficial?

Answer 1

External
Internal
Innermost/intimal

Question 2

What direction does the external intercostals fibres follow?

Answer 2

Oblique
(diagonally inwards)

Question 3

What direction does the internal intercostals fibres follow?

Answer 3

Diagonally outwards

Question 4

What direction does the innermost intercostals fibres follow?

Answer 4

Diagonally outwards

Question 5

Between which muscles dose the neurovascular bundle sit?

Answer 5

Between internal and innermost

Question 6

Why do the internal/innermost muscles run at right angles to the external muscles?

Answer 6

To provide strength to the muscle layers

Question 7

How is the intercostal space numbered?

Answer 7

According to the rib above
(e.g. 5th intercostal space is between ribs 5 and 6)

Question 8

In which part of the rib is the neurovascular bundle lodged?

Answer 8

Costal groove

Question 8

What is the clinical importance of the order of the neurovascular bundle?

Answer 8

The intercostal nerve is the lowest lying structure and therefore liable to damage if a chest drain is inserted into the pleural space too close to the inferior border of the rib.

Question 9

What part of respiration dose the intercostal muscles help with?

Answer 9

Inspiration

Question 10

What does the collateral branch of the neurovascular bundle supply?

Answer 10

The pleura and periosteum of the ribs

Question 11

Where should a chest drain needle be inserted to avoid damaging the main intercostal nerve?

Answer 11

Above the superior border of the lower rib