Thoracic Cage Anatomy

Thoracic Cage

• Protects the lungs and heart.

Sternum

• Located on the anterior side of the thoracic cage.
• Also known as the breastbone.
• Composed of three fused bones:
  • Manubrium:
    • Uppermost bone.
    • Site of clavicle attachment.
    • Site of first pair of ribs attachment.
  • Body:
    • Long, main part of the sternum.
    • Where multiple pairs of ribs attach.
  • Xiphoid Process:
    • Sharp point at the base of the sternum.
    • Attachment site for the Linea Alba.

Linea Alba

• Connective tissue that extends from the xiphoid process down the abdomen towards the pubic bones.
• Translates to "white line."
• Serves as connective tissue for abdominal muscles, such as the rectus abdominis.

Ribs

• There are 12 pairs, totaling 24 ribs.
• Named from top to bottom (pair one, pair two, etc.).

True Ribs

• Pairs one through seven.
• Have a direct cartilage attachment to the sternum.
• The cartilage between the ribs and the sternum is called costal cartilage.

False Ribs

• Pairs eight through twelve.
• Do not have a direct cartilage attachment to the sternum.
  • Example: The costal cartilage of pair nine joins the cartilage of pair eight, which then joins the cartilage of pair seven before connecting to the sternum.

Floating False Ribs

• Pairs eleven and twelve.
• Have no anterior attachment at all.