The subcostal nerve (anterior division of the twelfth thoracic nerve) is larger than the others. It runs along the lower border of the twelfth rib, often gives a communicating branch to the first lumbar nerve, and passes under the lateral lumbocostal arch.

Where does the Subcostal nerve originate?

It originates as the T12 root and travels with the subcostal vessels on the inferior aspect of the T12 rib to pierce the muscular aponeurosis to travel between the internal oblique and transversus abdominis.

Where is subcostal located?

Subcostal muscles are the thin muscles found on the inner surface of the posterior thoracic wall bridging two or three intercostal spaces. Together with the intercostal, serratus posterior, levatores costarum, and transversus thoracis muscles they comprise the intrinsic musculature of the chest wall.