Subcostal muscles

German: Musculi subcostales

1 Definition

The subcostal muscles are skeletal muscles which belong to the intercostal muscular system.

2 Alignment

The subcostal muscles derive from the musculi intercostales interni. Their fibers proceed in the same direction. They originate near to the angulus costae and are very developed in the caudo-dorsal area of the thorax. In their alignment to the upper oblique direction in most cases they skip the next upper rib and insert in the rib after.

3 Innervation

The subcostal muscles are innervated segmentally by the intercostal nerves. Even though the muscles overdraw several ribs, they are innervated by the fibers originated out of one vertebral segment.

4 Function

The subcostal muscles perfom the same function concerning the caudal thorax as the musculi intercostales interni. They lower the ribs and support the expiration.