Distinguishing the Axial and Appendicular Skeleton

Let's dive into how our skeleton is organized into two main divisions: the axial and appendicular skeleton. Think of it as nature's way of creating a framework that's both sturdy and flexible!

The Axial Skeleton

The axial skeleton forms the central core of our body and includes:

• Skull (cranium and facial bones)
• Vertebral column (spine)
• Sternum (breastbone)
• Ribs

Think of the axial skeleton as your body's central "axis" – it's the core structure from which everything else extends!

Key characteristics of the axial skeleton:

• Protects vital organs (brain, heart, lungs)
• Provides central support for the body
• Contains 80 bones in total
• Maintains vertical posture

The Appendicular Skeleton

The appendicular skeleton consists of the bones of our appendages (limbs) and their connecting girdles:

• Upper limbs (arms)
  • Humerus, radius, ulna
  • Carpals, metacarpals, phalanges
• Lower limbs (legs)
  • Femur, tibia, fibula
  • Tarsals, metatarsals, phalanges
• Shoulder girdle (pectoral)
  • Clavicle (collarbone)
  • Scapula (shoulder blade)
• Pelvic girdle
  • Hip bones (ilium, ischium, pubis)

The appendicular skeleton contains 126 bones and is primarily responsible for movement and manipulation of the environment.

Key Distinctions

Function

• Axial: Protection and support
• Appendicular: Movement and manipulation

Location

• Axial: Central core of body
• Appendicular: Attached to axial skeleton via girdles

Students often confuse the shoulder and pelvic girdles as part of the axial skeleton. Remember, these are part of the appendicular skeleton as they connect the limbs to the axial skeleton!