Anatomy of the Axial Skeleton

Axial Skeleton

The axial skeleton consists of 80 bones that make up the central axis of the body.

Divisions

• Cranium: 22 bones that form the skull
  • Protects the brain
  • Contains the sensory organs (eyes, ears, nose, mouth)
• Vertebral column: 33 bones that form the spine
  • Supports the head and body
  • Protects the spinal cord
• Thoracic cage: 28 bones that form the ribcage
  • Protects the heart and lungs
  • Provides attachment points for muscles

Functions

• Support: Provides a framework for the body's muscles, organs, and tissues
• Protection: Protects vital organs such as the brain, heart, and lungs
• Movement: Allows for movement and flexibility through the vertebral column and joints

Key Features

• Vertebrae: The 33 bones of the vertebral column are divided into 5 regions:
  1. Cervical (7)
  2. Thoracic (12)
  3. Lumbar (5)
  4. Sacrum (5 fused)
  5. Coccyx (4 fused)
• Rib types: There are 3 types of ribs:
  1. True ribs (1-7)
  2. False ribs (8-10)
  3. Floating ribs (11-12)

Development and Growth

• The axial skeleton develops from the embryonic mesoderm
• Ossification (bone formation) occurs through endochondral ossification (cartilage model) and intramembranous ossification (direct bone formation)

Axial Skeleton

• Comprises 80 bones forming the central axis of the body

Divisions

• Cranium: 22 bones forming the skull, protecting the brain and containing sensory organs
• Vertebral column: 33 bones forming the spine, supporting the head and body, and protecting the spinal cord
• Thoracic cage: 28 bones forming the ribcage, protecting the heart and lungs, and providing attachment points for muscles

Functions

• Support: Provides a framework for the body's muscles, organs, and tissues
• Protection: Protects vital organs such as the brain, heart, and lungs
• Movement: Allows for movement and flexibility through the vertebral column and joints

Key Features

• Vertebrae: 33 bones divided into 5 regions: cervical (7), thoracic (12), lumbar (5), sacrum (5 fused), and coccyx (4 fused)
• Rib types: 3 types of ribs: true ribs (1-7), false ribs (8-10), and floating ribs (11-12)

Development and Growth

• Develops from the embryonic mesoderm
• Ossification occurs through endochondral ossification (cartilage model) and intramembranous ossification (direct bone formation)

Learn about the 80 bones that make up the central axis of the body, including the cranium, vertebral column, and thoracic cage.