2.6. Location of the Intercostal Structures
The Intercostal Veins, Arteries and Nerves
There is an intercostal vein, artery and nerve running in each intercostal space. Look at the diagram and notice three things about these vessels and nerves...
They run in the costal groove of the rib associated with that space. The costal groove is found on the internal aspect of the rib, at the inferior part of the shaft of the rib. It is formed by the slight curvature in the bone. Notice that although the vessels and nerves are protected by bone, they are technically still 'intercostal'. For example, the 4th intercostal vessels and nerve run in the costal groove of the fourth rib (and as such they lie in the 4th intercostal space).
The vessels and nerves lie very close to each other and run in a particular order. From top-to-bottom (superior to inferior), they are the vein, artery and nerve. Confirm this in the accompanying diagram
The intercostal vessels and nerves run in-between the internal intercostal muscles and the innermost intercostal muscles proper.
At this stage, you might be wondering where the intercostal vessels and nerves originate - this is discussed in sections 4, 5 and 6.
Also, it might sound stupid to point out, but remember that the veins are running in the opposite direction to the arteries because they are draining the blood from the intercostal spaces.