Space
Intercostal space
Muscle and neurovascular layers between ribs
High-yield
The principal bundle lies between the internal and innermost layers. In its usual superior-to-inferior order, the vein is above the artery and the nerve is below it; collateral branches occupy another part of the space.
Overview
There are eleven intercostal spaces on each side, named for the rib above. Their layered walls contain muscles, vessels and nerves; endothoracic fascia and parietal pleura lie deeper toward the chest cavity.
Reference facts
- Boundaries
- Adjacent ribs and cartilages above and below; three intercostal muscle layers, with fascia and parietal pleura on the deep side
- Contents
- Intercostal muscles and the main vein–artery–nerve bundle near the upper rib's groove, smaller collateral branches, and anterior arterial connections
- Communications
- Posterior connections toward the paravertebral region; cutaneous branches reach the skin, and lower thoracic nerves continue into the abdominal wall
Mnemonic
Read the main bundle downward as V–A–N: vein, artery, nerve.
Clinical correlation
Both main and collateral vessels can be injured during chest-wall procedures. The muscle layers and rib borders provide orientation, but an access decision also depends on the underlying lung, diaphragm and any pleural fluid.
Frequently asked questions
What are the boundaries of the intercostal space?
Adjacent ribs and cartilages above and below; three intercostal muscle layers, with fascia and parietal pleura on the deep side.
What does the intercostal space contain?
Intercostal muscles and the main vein–artery–nerve bundle near the upper rib's groove, smaller collateral branches, and anterior arterial connections.
What does the intercostal space communicate with?
Posterior connections toward the paravertebral region; cutaneous branches reach the skin, and lower thoracic nerves continue into the abdominal wall.