The human skeleton is the internal framework of bones that gives shape to the body, supports movement, protects vital organs, and produces blood cells.
An adult human has 206 bones, while a newborn baby has about 270, many of which fuse together as they grow.
🧩 Main Parts of the Skeleton
The skeleton is divided into two major parts:
| Part | Description | Main Components |
|---|---|---|
| Axial skeleton | Central part of the body | Skull, spine (vertebrae), ribs, sternum |
| Appendicular skeleton | Limbs and girdles | Arms, legs, pelvis, shoulders |
🦴 Types of Bones
Bones come in different shapes and sizes:
| Bone Type | Example(s) | Function |
|---|---|---|
| Long bones | Femur (thigh), humerus (arm) | Support weight and facilitate movement |
| Short bones | Wrist (carpals), ankle (tarsals) | Provide stability and some movement |
| Flat bones | Skull, ribs, sternum | Protect organs and provide surface for muscles |
| Irregular bones | Vertebrae, pelvis | Complex shape for protection and support |
| Sesamoid bones | Patella (kneecap) | Protect tendons from stress and wear |
⚙️ Functions of the Skeleton
| Function | Description |
|---|---|
| Support | Holds the body upright and gives it shape |
| Protection | Shields vital organs (e.g. skull protects brain, ribcage protects heart/lungs) |
| Movement | Works with muscles to produce movement |
| Blood cell production | Bone marrow inside bones makes red and white blood cells |
| Mineral storage | Stores calcium and phosphorus for use in the body |
| Energy storage | Yellow marrow stores fat (energy reserve) in long bones |
🧠 Interesting Facts About the Skeleton
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The longest bone: Femur (thigh bone)
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The smallest bone: Stapes in the middle ear (~2.8 mm)
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The spine consists of 33 vertebrae at birth, but adults usually have 26 after some fuse
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The skull is made up of 22 bones
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Bones are living tissues that grow, repair, and renew themselves
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Bone marrow produces over 2 million blood cells per second!
🔍 Examples of Key Bones
| Bone | Location | Function |
|---|---|---|
| Skull | Head | Protects the brain |
| Spine (vertebral column) | Back | Supports body, protects spinal cord |
| Rib cage | Chest | Protects heart and lungs |
| Humerus | Upper arm | Allows arm movement |
| Femur | Upper leg | Supports body weight when standing |
| Pelvis | Hip area | Supports organs and connects legs |
✅ Skeleton Summary Table
| Section | Bones Included | Function |
|---|---|---|
| Axial skeleton | Skull, spine, ribs, sternum | Protection and support for vital organs |
| Appendicular | Arms, legs, shoulder and pelvic girdles | Movement and flexibility |