Eleventh rib

Costa fluitans XI

SkeletalSkeletonThoraxLeft and right

View left in 3D View right in 3D

What it is
The eleventh rib, a floating rib: a curved flattened bar whose head articulates with T11, its tubercle with the T11 transverse process, sloping down and forward to its costal cartilage.
Function
Protects the thoracic organs and moves up and out with the intercostal muscles during breathing (bucket-handle motion).
Size
Cross-section ≈ 6 × 11 mm; arc length ≈ 20 cm
Clinical note
Floating ribs end free in the flank muscles and have no anterior attachment.

Nearby skeletal structures Eighth rib, Eleventh costal cartilage, Intervertebral disc T10–T11, Intervertebral disc T11–T12, Intervertebral disc T12–L1, Ninth rib, T10 vertebra, T11 vertebra, T12 vertebra, Tenth rib