Muscle · Chest

Innermost intercostal

Musculi intercostales intimi

The deepest of the three muscular layers between the ribs, lying against the inner surface of the chest wall with its fibres running the same way as the internal intercostals it is separated from. That separation is the fact worth carrying: the intercostal nerve and the intercostal artery and vein run in the plane BETWEEN the internal and the innermost layer, sheltering under the lower border of the rib above. It is best formed in the middle of each space, in the lower part of the chest, and it acts with the rest of the intercostal set to hold the space firm and move the rib below.