Definitions

1. adjective

relating to or affecting the muscles and ribs, especially in reference to the lower ribs (9th to 12th) and their associated muscles.

“The iilocostal muscles were affected by the injury, causing her immense pain.”

2. noun

the muscles and ribs, especially the lower ribs (9th to 12th) and their associated muscles.

“The iilocostal region is a common site for thoracic injuries.”