Muscle · Thoracic spine

Levatores costarum

Musculi levatores costarum

Twelve small fan-shaped muscles on each side of the thoracic spine, each running from a transverse process downward and outward to the rib below, between that rib's tubercle and its angle. They sit deep to the erector spinae and belong to the back by position but to the rib cage by attachment — a direct muscular link between the spine and each rib in turn. The lowest four are longer and skip a rib. Their named action is to lift the rib they hold, but each one is short and the leverage small, so what they contribute to a breath is a steadying of the rib on the vertebra rather than a large excursion.