Joints
Sternocostal joints (artt. sternocostales)
The connection of the costal cartilage to the sternum, for the seven true ribs. The first costal cartilage is fused with the manubrium and does not move; from the second rib these are small joints with a capsule, and it is those that give the chest its springiness.
- Joint type
- First rib a synchondrosis, ribs 2 to 7 true joints with a capsule
- Latin name
- Articulationes sternocostales
Movements, axes and normal values
| Movement | Plane | Axis | Normal range | End feel |
|---|---|---|---|---|
| Rib elevation on inspiration | combined | oblique, along the axis of the rib neck | torsion of the costal cartilage as the rib rises; the cartilage itself deforms with it | firm springy (ligament) |
- Close-packed position
- Full inspiration
- Resting (loose-packed) position
- Quiet expiration
- Capsular pattern
- Local tenderness and pain on deep inspiration; no true capsular pattern.
- Arthrokinematics
- The costal cartilage works as a torsion spring: on inspiration it twists about its long axis and stores elastic energy, released again on expiration. Quiet expiration therefore costs no muscle work. With age this cartilage calcifies and the chest becomes stiffer.
- Stability
- The radiate sternocostal ligaments front and back, which together with the periosteal fibres form a weave across the sternum.
- Palpation
- The sternal angle is the counting landmark: that transverse ridge at the level of the second rib is found by stroking down from the jugular notch. Count the ribs from there; the small joints lie as slight elevations right beside the sternal border.
- Clinical
- Tietze syndrome and costochondritis cause chest pain that can be reproduced exactly by pressing these joints: valuable, because it makes a cardiac cause less likely. Reproducibility on palpation does not rule a cardiac problem out, however, so when in doubt keep following the usual red flags.
- Source
- Speciële anatomie van het houdings- en bewegingsapparaat (HU, 2013); BOKS anatomie Levensfasen (HU, 2024)