Expansion
Manubrium, body and xiphoid process, with marrow aspirated from the body at the level of the second space
Expansion
Three parts, from top down:
- Manubrium - articulates with the clavicles and first costal cartilages
- Body - articulates with costal cartilages 2 to 7
- Xiphoid process - cartilaginous in youth, ossifying by about 40
The manubriosternal joint at the sternal angle is a symphysis; the xiphisternal joint lies at about T9.
The sternum retains red marrow throughout life, so it can be used for marrow aspiration. The safe site is the body of the sternum in the midline at the level of the second intercostal space, entered at a shallow angle; the posterior table is thin and the aortic arch and right ventricle lie immediately behind.