Lecture Notes: Examination of the Thoracic Cage

Functions of the Thoracic Cage

• Protects vital organs of the thoracic cavity (heart, lungs, major blood vessels).
• Supports shoulder girdles (clavicle, scapula, shoulder joints) and upper limbs.
• Provides attachment sites for muscles (neck, back, chest, shoulders).

Structure of the Thoracic Cage

• Posterior Side: Comprised of thoracic vertebra.
• Anterior Side: Made up of sternum and costal cartilages.
• Lateral Sides: Consist of ribs.

Components of the Sternum

• Manubrium:
  • Superior portion of the sternum.
  • Clavicular notch: Articulation with clavicles.
  • Jugular notch: Located at the disc between vertebra T2 and T3; relevant to the carotid artery.
  • Articulates with the first two pairs of ribs.
• Body of the Sternum:
  • Articulates with costal cartilages from ribs 2 through 7.
  • Sternal angle: Intersection of manubrium and body; corresponds to T4, T5.
• Xiphoid Process:
  • Inferior end; muscle attachment site.
  • No rib attachments.
  • Ossifies around age 40.
  • Xipho-sternal joint: Meets sternal body; corresponds to thoracic vertebra nine.

Ribs Overview

• 12 Pairs of Ribs:
  • Attached to the breastbone and thoracic vertebrae.
  • Posterior Attachments:
    • Transverse processes of thoracic vertebra (transverse costal facet).
    • Superior costal facet for head of rib.
• Anterior Attachments:
  • Via costal cartilage to the breastbone.

Classification of Ribs

• True Ribs (Pairs 1-7):
  • Directly attached to the sternum via individual costal cartilages.
• False Ribs (Pairs 8-12):
  • Not directly attached to the sternum.
  • Vertebrochondral Ribs (Pairs 8-10):
    • Attached to the costal cartilage of the rib above.
  • Floating Ribs (Pairs 11-12):
    • No attachment to the sternum.
    • No associated costal cartilage.

Specific Parts of a Rib

• Shaft: Majority of the rib.
• Head:
  • Articulates with vertebra (superior costal facet).
• Neck: Constricted portion beyond the head.
• Tubercle:
  • Lateral to the neck.
  • Articulates with the transverse costal facet.

Summary

This lecture provided an in-depth review of the thoracic cage, its protective and supportive functions, the structural components of the sternum, and the classification and specific parts of ribs. Understanding these details is crucial for comprehending how the thoracic cage supports vital bodily functions and structures.