Twelfth rib at a glance
- Also called
- Rib 12
- What it is
- The twelfth rib. The lowest floating rib, often very short, with no neck or tubercle.
- Location
- Part of the thoracic cage, curving from the twelfth thoracic vertebra behind around the chest wall toward the front. A floating rib.
- Function
- Protects the thoracic organs and, by moving at its vertebral joints, changes chest volume during breathing.
- Body system
- Skeletal · paired (left and right)
- FMA ID
- FMA8534 (Foundational Model of Anatomy)
Key facts
- Its head has a single facet for T12; it lies behind the upper part of the kidney and gives attachment to quadratus lumborum and the diaphragm.
- Its length varies; it can be shorter than the first rib or longer than the eleventh.
Clinical relevance
The pleura dips below the medial part of the twelfth rib, so it can be opened in a posterior approach to the kidney; a short twelfth rib can be mistaken for the eleventh when counting.
Structures next to the twelfth rib
The nearest named structures in the 3D model, measured from the centre of each part:
- Subcostal vein · cardiovascular
- Eleventh rib · skeletal
- Subcostal artery · cardiovascular
- Serratus posterior inferior · muscular
- Kidney · urinary
- Iliocostalis lumborum · muscular
- Suprarenal vein · cardiovascular
- Inferior suprarenal artery · cardiovascular
- Adrenal gland · endocrine
- Lumbar rotator · muscular
References
- Foundational Model of Anatomy: Twelfth rib (FMA8534). EMBL-EBI Ontology Lookup Service.
- OpenStax. Anatomy and Physiology 2e, §7.1 Divisions of the Skeletal System. Rice University, 2022.
- Mitsuhashi N. et al. (2009). BodyParts3D: 3D structure database for anatomical concepts. Nucleic Acids Research 37, D782–D785. Data © The Database Center for Life Science, CC BY 4.0.
Related anatomy
Explore the whole body in the interactive 3D human anatomy model, or browse the A–Z list of human structures.