BoneFlat bone

Rib 12 (left) — floating rib

Latin: Costa XII sinistra

Location: Posterior lower thorax

View the rib 12 (left) — floating rib in 3D

Function

The shortest rib — a mere splinter of bone anchoring the quadratus lumborum, latissimus dorsi and diaphragm over the kidney.

Landmarks

  • Single facet
  • Very short shaft

Articulations (joints)

  • T12 vertebral body only

Clinical relevance

A hypoplastic twelfth rib can be congenitally absent; kidney surgeons use it as the landmark for the lumbotomy incision.

Educational anatomy reference, not medical advice. About this content.