The sternum completes the anterior chest wall as the ventral breastplate.

The sternum is composed of a manubrium, a body and the inferior xiphisternum or xiphoid process. These articulations are via hyaline cartilage with a fibrocartilaginous intervening disc: 

  • the manubrium is flat and four-sided, wider superiorly
  • the body is a flat rectangular bone that has grooves (facets) on its lateral border for articulation with the ribs:
    • approximately 20 cm long
    • 3-4 cm wide
    • 1 cm thick
  • the xiphoid process is a thin bony projection inferiorly
  • superiorly the manubrium attaches to the neck where the two deep layers of cervical investing fascia insert
  • the manubrium articulates with the first rib and clavicle
  • the body articulates with the second rib at the angle of Louis as well as the 2nd to 7th rib and costal cartilages
  • inferiorly articulates with xiphoid cartilaginous joint
  • muscular attachments: sternocleidomastoid, intercostal muscles, pectoralis major, sternohyoid, sternothyroid
  • transversus thoracis arises from the posterior surface of the body
  • the xiphisternum attaches to linea alba
  • sternopericardial ligaments secure the fibrous pericardium to it
  • interclavicular ligament
  • anterior and posterior sternoclavicular ligaments (thickenings of the sternoclavicular joint capsule)
  • nerve supply is via anterior intercostal nerves
  • chain of internal mammary lymph nodes
Anatomy: Thoracic
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Article information

rID: 46816
System: Chest
Section: Anatomy
Synonyms or Alternate Spellings:
  • Sternum (anatomy)
  • Breastbone

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