Posterior intercostal arteries (3rd–11th)
Branch · Spaces 3–11 Costal groove VAN
Nine pairs from the back of the descending thoracic aorta for the 3rd to 11th intercostal spaces (the 1st and 2nd come from the supreme intercostal branch of the costocervical trunk), plus the subcostal arteries below the 12th rib. Each runs in the costal groove beneath its rib with the vein above and nerve below and anastomoses anteriorly with anterior intercostal branches of the internal thoracic artery.
Traced from the start
- Descending thoracic aorta
- Posterior intercostal arteries (3rd–11th)
Detail
- Supplies
- Intercostal muscles, parietal pleura, breast, skin and muscles of the back
- Dorsal branch
- Gives a spinal branch through the intervertebral foramen to vertebra, meninges and cord (radicular arteries)
- Costal groove order
- Vein, artery, nerve from above down (VAN), so the bundle hugs the lower border of the rib
When it goes wrong
Chest drain or intercostal block placed at the lower border of a rib
Injury to the bundle in the costal groove: haemothorax from the posterior intercostal artery; go in at the upper border of the rib below
Coarctation of the aorta
Retrograde flow from the internal thoracic through dilated posterior intercostals to the aorta notches the inferior borders of ribs 3–9 on chest X-ray
Practise this structure
3 questions in the bank tagged Thorax.
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