Rib 12
Costa XII
- Related terms: Rib [XII]
Definition
The rib 12 (twelfth rib), is as the floating rib, is the last and most caudal rib in the human ribcage.
It is shorter and less curved than the other ribs and does not attach to the sternum or the costal cartilage of other ribs. Anatomically, the twelfth rib has a head that articulates with the T12 vertebra, but it lacks a neck and tubercle, which are present in the more superior ribs.
The anterior end of the twelfth rib is free and does not connect to any other structure, which is why it is termed a "floating" rib. The twelfth rib provides attachment points for muscles such as the quadratus lumborum and the diaphragm, playing a role in the movement and stabilization of the lower thoracic and upper lumbar regions.[1-2]
References
1.The Ribs: Anatomic and Radiologic Considerations.Kurihara Y, Yakushiji YK, Matsumoto J, Ishikawa T, Hirata K.Radiographics : A Review Publication of the Radiological Society of North America, Inc. 1999 Jan-Feb;19(1):105-19; quiz 151-2. doi:10.1148/radiographics.19.1.g99ja02105.
2.Surgical Anatomy of the 10th and 11th Intercostal, and Subcostal Nerves: Prevention of Damage During Lumbotomy.van der Graaf T, Verhagen PC, Kerver AL, Kleinrensink GJ.The Journal of Urology. 2011;186(2):579-83. doi:10.1016/j.juro.2011.03.120.
