Intercostal spaces (dave's notes)

Question 1

Where in the intercostal space is the vein, artery and nerve found?

Answer 1

In between the middle and inner layers, in the neuromuscular plane, under the protection of the lip of the rib.
There are collateral branches running along the upper border but these can be ignored

Question 2

From what does the intercostal nerve arise?

Answer 2

They are a continuation of the mixed spinal nerve once it has given off its posterior ramus

Question 3

Where does the intercostal nerve run? What branches does it give off?

Answer 3

The intercostal nerve runs between the internal interocostal and the transversus thoracic group, giving a branch to supply the muscles of the space.
The main nerve has a lateral cutaneous branch and a terminal anterior cutaneous branch

Question 4

Describe the lateral cutaneous branch of the intercostal nerve

Answer 4

The lateral cutaneous branch pierces the overlying muscles dividing into anterior and posterior branches

Question 5

Describe course of the anterior cutaneous branch of the intercostal nerve

Answer 5

The anterior cutaneous branch in the upper 6 spaces passes anterior to the internal thoracic artery, then pierces the muscle to the skin.

Question 6

What supplies the skin to the anterior abdominal wall?

Answer 6

The lower five intercostal nerves slope downwards to supply the anterior abdominal wall

Question 7

Describe the first intercostal nerve

Answer 7

Very small, supplies no skin

Question 8

Describe the course of the subcostal nerve

Answer 8

this passes quickly into the abdominal cavity behind the lateral arcuate ligament

Question 9

Which lies more superficial/takes a wider path - artery or nerve?

Answer 9

In general, the nerve does

Question 10

Where do arteries enter the intercostal space?

Answer 10

At the front and back.

Question 11

Posteriorly: What supplies the upper two spaces? From whence does it arise?

Answer 11

The superior intercostal artery, arising from the costocervical trunk, subclavian part 2 XXX?Dave thinks of import.

Question 12

Posteriorly: What is the arterial supply of spaces 3-11?

Answer 12

The thoracic aortic branches with each giving a small collateral branch

Question 13

Anteriorly: From what do the anterior intercostal arteries arise from?

Answer 13

The internal thoracic artery supplies the upper six spaces, and the musculophrenic (a continuation of the internal thoracic) supplies the 7th, 8th, and 9th spaces

Question 14

Describe the veins of the intercostal space

Answer 14

In each space there is one posterior and two anterior veins that accompany the arteries

Question 15

The posterior intercostal veins are not regular. List the deviations.

Answer 15

1st space: drained by the highest/supreme interocostal vein - to the vertebral/brachiocephalic vein
2nd and 3rd space: via the superior intercostal vein - in the right drains to the azygous, and on the left to the brachiocephalic
Lower 8 spaces: drain to the azygous system (azygous on the right, hemi-azygous on the left).

Question 16

Describe the lymphatic drainage of the intercostal spaces

Answer 16

Deep lymphatics follow arteries. Anteriorly these drain to intercostal/parasternal nodes. Posteriorly these drain to the intercostal nodes.

Question 17

From what does the internal thoracic artery arise? What is its path?

Answer 17

From the first part of the subclavian artery, and passes vertically down, just lateral to the sternum. Diveds at the costal margin to the epigastric and musculophrenic. Each interocostal space receives two arteries.

Question 18

Which are the largest perforating branches of the internal thoracic artery? What do these supply?

Answer 18

The 2nd and 3rd spaces, these also supply the breast.

Question 19

What is the subpleural membrane? What are its attachments?

Answer 19

A dense layer attached to the inner border of the first rib and costal cartilage, giving rigidity to the thoracic inlet to prevent distortion.