Sternum

Study entry

Parts

A flat, elongated bone in the middle of the anterior chest wall, over the mediastinal viscera and a good part of the heart. Three parts: manubrium (above, the widest and thickest), body (longest, narrow and thin, at the level of T5–T9) and xiphoid process (the smallest and most variable, cartilaginous in the young and ossified after 40). The parts are joined by synchondroses, which ossify in middle age or later.

Joints

Sternoclavicular (clavicular notches with the clavicles); synchondrosis of the 1st rib (lateral border of the manubrium with the 1st costal cartilage); sternocostal (costal notches with the cartilages of the true ribs); manubriosternal and xiphisternal between the parts.

Palpation

Subcutaneous and palpable along its whole length, in the anterior midline.

Clinical

The xiphoid process lies in a slight depression, the epigastric fossa, which guides the position of the hand on the lower sternum in cardiopulmonary resuscitation.

Source: cap. 4, «Esternón» y «Anatomía de superficie de la pared torácica»

Other structures in this region

• Typical rib (3rd–9th)
• 1st rib
• 2nd rib
• 10th rib
• 11th and 12th ribs
• Costal cartilages