Axial Skeleton Overview

Axial Skeleton Overview

• Definition: The axial skeleton is the central core of the human skeleton, consisting of bones that support and protect the brain, spinal cord, and thoracic organs.

Major Components

1. Skull

   • Composed of 22 bones.
   • Divided into two parts:
     • Cranial bones (8): Protect the brain.
     • Facial bones (14): Form the face structure and support.

2. Vertebral Column

   • Made up of 33 vertebrae.
   • Divided into five regions:
     • Cervical (7 vertebrae): Neck region.
     • Thoracic (12 vertebrae): Upper back, articulate with ribs.
     • Lumbar (5 vertebrae): Lower back, larger and bear weight.
     • Sacral (5 fused vertebrae): Form the sacrum.
     • Coccygeal (4 fused vertebrae): Form the coccyx (tailbone).

3. Thoracic Cage

   • Composed of:
     • Ribs (24 total): 12 pairs; protect thoracic organs.
     • Sternum (1): Breastbone; provides attachment for ribs.

Functions

• Support: Provides structural support for the body.
• Protection: Encases vital organs (e.g., brain, heart, lungs).
• Movement: Serves as attachment points for muscles, facilitating movement.
• Hematopoiesis: Some bones (e.g., ribs, vertebrae) are involved in blood cell production.
• Mineral Storage: Stores minerals like calcium and phosphorus.

Notable Features

• Curvatures: The vertebral column has normal curves (cervical, thoracic, lumbar) that enhance strength and flexibility.
• Intervertebral Discs: Cartilaginous structures that provide cushioning between vertebrae.

Clinical Relevance

• Spinal Disorders: Conditions like scoliosis, herniated discs, and degenerative disc disease affect the axial skeleton.
• Fractures: Skull and vertebrae fractures can result from trauma and may lead to severe complications.
• Arthritis: Joint inflammation in the vertebral column can lead to pain and reduced mobility.

Axial Skeleton Overview

• Central core of the human skeleton, protecting critical components like the brain, spinal cord, and thoracic organs.

Major Components

• Skull: Comprises 22 bones.

  • Cranial bones: 8 bones that encase the brain.
  • Facial bones: 14 bones that form facial structure and provide support.

• Vertebral Column: Consists of 33 vertebrae, segmented into five regions.

  • Cervical region: 7 vertebrae located in the neck.
  • Thoracic region: 12 vertebrae that make up the upper back and connect to ribs.
  • Lumbar region: 5 larger vertebrae in the lower back, designed for weight support.
  • Sacral region: 5 fused vertebrae forming the sacrum.
  • Coccygeal region: 4 fused vertebrae forming the coccyx or tailbone.

• Thoracic Cage: Offers protection for thoracic organs.

  • Ribs: Total of 24, comprising 12 pairs that shield heart and lungs.
  • Sternum: A single breastbone, serves as a connection point for ribs.

Functions

• Support: Structural framework for the body’s shape and posture.
• Protection: Safeguards vital organs such as the brain, heart, and lungs.
• Movement: Muscle attachment provides leverage for motion.
• Hematopoiesis: Blood cell production occurs in certain bones like ribs and vertebrae.
• Mineral Storage: Reservoir for essential minerals, notably calcium and phosphorus.

Notable Features

• Curvatures: Vertebral column exhibits natural curves (cervical, thoracic, lumbar) enhancing stability and flexibility.
• Intervertebral Discs: Cartilaginous pads that cushion adjacent vertebrae, facilitating shock absorption and movement.

Clinical Relevance

• Spinal Disorders: Conditions such as scoliosis, herniated discs, and degenerative disc disease impact overall spinal health.
• Fractures: Trauma-related fractures in the skull or vertebrae can result in severe complications, affecting neurological function.
• Arthritis: Inflammation in the vertebral column can lead to pain and decreased mobility, impacting daily activities.