Intercostal space Flashcards
(33 cards)
Where is the intercostal space located anatomically?
Between the sharp lower border of the rib above and the smooth upper border of the rib below
What are the three layers of muscles filling the intercostal space?
External intercostal, internal intercostal, innermost intercostal muscles
Where does the neurovascular bundle lie within the intercostal muscles?
Between the internal and innermost intercostal muscles (neurovascular plane)
How is the neurovascular bundle arranged in the costal groove?
Vein, Artery, Nerve (VAN) from above downwards
Why is the arrangement of VAN clinically important?
Important for pleural drainage and thoracotomy
Where do intercostal nerves emerge from?
Intervertebral foramen
Which branch of the intercostal nerve runs above the lower rib in the space?
Collateral branch
Name the three branches of the intercostal nerves.
Collateral, lateral cutaneous, anterior cutaneous
Where is the intercostal nerve in relation to the artery anteriorly and posteriorly?
Superficial to the artery
Where does the intercostal nerve lie in the costal groove?
Lowest (beneath artery and vein)
Where do the lower 5 intercostal nerves and collateral branches run in the abdomen?
In the neurovascular plane of the abdominal wall
Which intercostal nerve is small and lacks a cutaneous branch?
1st intercostal nerve
Which nerve passes behind the lateral arcuate ligament into the abdomen?
Subcostal nerve (12th)
Which arteries supply the posterior intercostal spaces?
Superior intercostal artery (1st & 2nd), thoracic aorta (remaining spaces)
What are the sources of anterior intercostal arteries?
Internal thoracic artery (spaces 1–6), musculophrenic artery (spaces 7–9)
How many anterior intercostal arteries are there per space?
2
How do the anterior and posterior intercostal arteries interact in each space?
Two anterior branches anastomose with one posterior branch
Into what veins do the anterior intercostal veins drain?
Internal thoracic and musculophrenic veins
Into what system do the posterior intercostal veins drain?
Azygos system of veins
How do posterior intercostal veins from the right 4th to 11th spaces drain?
Into the azygos vein
How do posterior intercostal veins from the left 4th to 11th spaces drain?
Into hemiazygos and accessory hemiazygos veins
Where do hemiazygos and accessory hemiazygos veins eventually drain?
Azygos vein (after crossing to the right)
What vein drains the 1st intercostal space?
Supreme intercostal vein
Where does the supreme intercostal vein drain?
Brachiocephalic vein (both sides)
