Understanding the Human Skeletal System: Axial & Appendicular

The skeletal system is divided into two main parts:

Axial Skeleton

Includes bones of the head, neck, and trunk. It protects the brain, spinal cord, and vital organs.

• Skull: 22 bones protecting the brain, eyes, ears, nose, and mouth.
• Vertebrae: 33 bones forming the spine, divided into cervical (7), thoracic (12), lumbar (5), sacral (5), and coccygeal (4).
• Ribs: 12 pairs forming the rib cage, protecting the heart and lungs.
• Sternum: Flat bone connecting the ribs at the front of the chest.

Appendicular Skeleton

Includes bones of the limbs and their girdles, providing support and enabling movement.

• Shoulder Girdle: Clavicle (collarbone) and scapula (shoulder blade), connecting the arm to the torso.
• Upper Limb: Humerus (upper arm), ulna and radius (forearm), carpals, metacarpals, and phalanges (hand).
• Pelvic Girdle: Hip bones (coxal bones), fused from ilium, ischium, and pubis, connecting the legs to the torso.
• Lower Limb: Femur (thigh), tibia and fibula (leg), tarsals, metatarsals, and phalanges (foot).

Beyond structure and movement, the skeletal system stores minerals, produces blood cells, and plays a role in hormone regulation.