Anatomy & Physiology

Lesson 3 of 20

Body regions & cavities

Regional terms identify major areas, while cavities protect and organize internal organs. The axial body includes head, neck, and trunk; appendages form the limbs. Membranes line cavities and can reduce friction around moving organs. Surface landmarks help communicate location without implying diagnosis.

Key points

• The thoracic cavity contains the lungs and mediastinal structures, including the heart.
• The abdominal and pelvic cavities together form the abdominopelvic cavity.
• The cranial cavity houses the brain; the vertebral canal encloses the spinal cord.
• Serous membranes have parietal and visceral layers around select organs.
• Quadrants and regions divide the abdomen for clear location descriptions.

Key terms

Thoracic cavity

Chest cavity containing lungs and mediastinum.

Abdominopelvic cavity

Continuous cavity containing many digestive, urinary, and reproductive organs.

Mediastinum

Central thoracic region between the lungs.

Parietal layer

Serous membrane layer lining a cavity wall.

Visceral layer

Serous membrane layer associated directly with an organ surface.