Human Skeleton
Primary 4 · Science and Elementary Technology
Human Skeleton
Lesson 1 of 4
15 min
Let's begin
At the health centre, Habimana sees an X-ray photo of his aunt's arm hanging on a light box. Inside the grey shape of her arm are clear white bones! "Everyone has bones like that inside," the nurse says. "Together they make your skeleton."
Your skeleton is the frame of bones inside your body. A new-born baby has about 300 bones. As a child grows, some of them join together, so an adult has 206 bones. Bones are alive: they grow with you and are at their strongest when you are about 20 years old.
| Part | Bones (everyday name and science name) |
|---|---|
| Skull | the brain case (cranium) and the lower jaw (mandible). The jaw is the only skull bone that moves. |
| Backbone (spine, or vertebral column) | a chain of small bones called vertebrae, from the neck down to the tailbone |
| Ribcage | 12 pairs of ribs and the breastbone (sternum) |
| Shoulder girdle | collarbone (clavicle) and shoulder blade (scapula) |
| Arms and hands | upper arm bone (humerus); two forearm bones (radius and ulna); wrist bones (carpals); finger bones (phalanges) |
| Hip girdle (pelvis) | the wide hip bones that hold up the body and join the legs to it |
| Legs and feet | thigh bone (femur), the longest and strongest bone in the body; kneecap (patella); two shin bones (tibia and fibula); ankle bones (tarsals); toe bones (phalanges) |
The smallest bones in your body are the three tiny bones inside your ear.
Tip
Head to toe: Skull, Spine, Ribs, Arms, Hips, Legs
The Femur is the First in size: the longest bone.
Try each one first, then tap Show answer to check.
How many bones does an adult have?
Answer: 206.
Which is the longest bone in the body?
Answer: The thigh bone (femur).
Which bones make up the ribcage?
Answer: The ribs (12 pairs) and the breastbone.
Name the two bones of the forearm.
Answer: The radius and the ulna.
Which bone of the skull can move?
Answer: The lower jaw (mandible).
What you learned today
Sources and credits
The exercises (Try it yourself and the practice questions) are written by Ganzaa.
This lesson adapts CC BY-SA material and is shared under CC BY-SA 4.0.
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