JointThorax

Joints of the heads of the ribs (costovertebral)

articulationes capitis costarum

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Study entry

Classification

Synovial plane joint.

Surfaces

The head of each rib with the superior costal facet of the body of the vertebra of the same number, the inferior costal facet of the vertebra above and the intervertebral disc between them (for example, the 6th rib with T6, T5 and the T5-T6 disc). The heads of the 1st, 11th and 12th ribs (sometimes also the 10th) articulate only with the body of the vertebra of the same number.

Capsule

The crest of the head of the rib is joined to the disc by an intra-articular ligament, which divides the joint into two synovial cavities. The fibrous membrane is stronger in front, where it forms the radiate ligament of the head of the rib, fan-shaped, from the anterior border of the head to the sides of the bodies of the two vertebrae and of the disc between them.

Movements

Only slight gliding movements on the demifacets (around the intra-articular ligament), which nevertheless cause relatively large displacement of the anterior end of the rib. Movement of the ribs (mainly 2nd to 6th) about an axis that passes through the neck raises the anterior ends, the «pump-handle» movement, and increases the anteroposterior diameter of the thorax.

Blood supply

[CHECK: Moore does not describe it in the passages consulted (look in another source).]

Innervation