Body Cavities

BODY CAVITIES

Body cavities are hollow spaces within the body that protect internal organs and allow them to function without interference from one another. They also provide room for organs to expand or move.

There are two major categories of body cavities:

1. Dorsal Body Cavity (Posterior)

This cavity protects organs of the nervous system.

a) Cranial Cavity

• Contains the brain.
• Formed by skull bones:
• Front: Frontal bone
• Sides: Temporal bones
• Back: Occipital bone
• Top: Parietal bones
• Bottom: Sphenoid and Ethmoid bones

b) Vertebral (Spinal) Cavity

• Formed by the vertebral column.
• Contains:
• Spinal cord
• Spinal nerve roots
• Protects a major part of the central nervous system.

2. Ventral Body Cavity (Anterior)

Located in the front of the body; contains many vital organs.

a) Abdominal Cavity

• Largest cavity in the body; oval-shaped.
• Boundaries:
• Superior: Diaphragm
• Anterior: Abdominal muscles
• Posterior: Lumbar vertebrae and muscles
• Lateral: Lower ribs
• Inferior: Continuous with the pelvic cavity
• Lined by peritoneum, a protective membrane.

b) Thoracic Cavity

• Located in the upper trunk.
• Boundaries:
• Front: Sternum and rib cartilages
• Sides: Ribs and intercostal muscles
• Back: Thoracic vertebrae
• Top: Structures of neck root
• Bottom: Diaphragm
• Contains heart, lungs, major blood vessels.

c) Pelvic Cavity

• Funnel-shaped; continuation of abdominal cavity.
• Boundaries:
• Superior: Abdominal cavity
• Anterior: Pubic bones
• Posterior: Sacrum and coccyx
• Lateral: Hip bones
• Contains urinary bladder, reproductive organs, and lower digestive tract.