Organization of the Human Body: Axial Region and Cavities

Overview

• The human body can be divided into two main regions:
  • Axial Region: Includes the head, neck, and trunk.
  • Appendicular Region: Includes extremities (upper and lower limbs with girdles). This will be discussed later in the context of the skeleton.

Axial Region

• Focus of the discussion.
• Contains two major cavities:
  • Ventral Body Cavity
  • Dorsal Body Cavity

Dorsal Body Cavity

• Located posteriorly (toward the back).
• Contains two smaller cavities:
  • Cranial Cavity
    • Superior position.
    • Contains the brain.
    • Bony protection by the skull.
  • Vertebral Canal (Column)
    • Contains the spinal cord.
    • Protected by vertebrae.
• Both cavities are continuous, meaning there is no physical separation between them.

Ventral Body Cavity

• Located anteriorly (toward the front).
• Larger cavity, further subdivided:
  • Thoracic Cavity
    • Superior position.
    • Contains smaller cavities:
      • Pleural Cavities: Hold the lungs (two plural cavities for two lungs).
      • Pericardial Cavity: Holds the heart (medial to the pleural cavities).
      • Mediastinum: A wall of organs superior to the pericardial cavity and medial to the lungs, includes esophagus, trachea, thymus, and blood vessels.
  • Abdominopelvic Cavity
    • Separated from the thoracic cavity by the diaphragm (a respiratory muscle).
    • Further subdivided:
      • Abdominal Cavity
        • Superior component.
        • Contains organs such as liver, stomach, small intestine, spleen, and kidneys.
      • Pelvic Cavity
        • Inferior component.
        • Contains reproductive organs, urinary bladder, and others.
    • The separation between abdominal and pelvic cavities is imaginary.

Summary

• Focused on the axial region and its cavities.
• Discussed the ventral and dorsal cavities and their subdivisions.
• Provided examples of organs found in each cavity.