Bones and joints
Match cartilage and ligaments to their roles, and identify fractures, sprains, dislocations and arthritis.
On this page
Staying Healthy · about 25–35 min
What you need to understand
Ligament: bone to bone. Sprain: ligament. Fracture: bone.
Definitions
- osteoporosis
loss of bone strength or density that increases fracture risk
For example: Diet and suitable weight-bearing activity support bone health.- ligament
a strong band joining bone to bone and helping stabilise a joint
For example: A sprain stretches or tears a ligament.- arthritis
inflammation or damage affecting a joint
For example: Arthritis can cause pain, stiffness and reduced joint movement.
Key idea
- LookA joint is twisted and the tissue joining bone to bone is overstretched.
- ThinkLigament: bone to bone. Sprain: ligament. Fracture: bone.
- DoMatch a structure or condition to its description and connect diet and physical activity to risk.
Explanation
Cartilage forms a smooth covering on the facing bone ends, reducing friction as a joint moves. It is not the band joining the bones. A ligament joins bone to bone and helps keep them aligned while allowing normal movement. A fracture is a broken or cracked bone; arthritis involves inflammation or damage at a joint; a sprain stretches or tears a ligament; and a dislocation moves bones out of their normal position.
Calcium and vitamin D support bone health, while suitable weight-bearing activity supports strength. Osteoporosis reduces bone strength or density and raises fracture risk. Helpful activity should be appropriate; unsafe excessive loading can also cause injury.
Pause and say it: Ligament: bone to bone. Sprain: ligament. Fracture: bone.
Common mistake
Tempting wrong idea: “A sprain and a fracture both hurt, so they must both be breaks in a bone.”
Why it fails: Each condition is named by what has happened: a fracture is a break or crack in a bone, a sprain is a stretched or torn ligament, and osteoporosis is bone becoming weak and brittle. Giving one condition’s feature to another leads to the wrong description of the injury.
Use this instead: A crack is a fracture, while the stretched ligament is a sprain. An injury does not automatically cause osteoporosis.
Practical work
What to show: Match a structure or condition to its description and connect diet and physical activity to risk.
Before you finish: Unsafe excessive loading can itself cause injury.
Practical link: The topic investigation is taught in “BMI and weight decisions”
6. Worked Examples
Modelled example 1
Identify an injured structure
Problem
A joint is twisted and the tissue joining bone to bone is overstretched. Name the tissue and the injury described, explaining how the evidence supports your identification.
Study the worked solution
Reason from the evidence
Method
Translate “bone to bone” into the named tissue, then classify the injury to that tissue.
Reason
Ligaments stabilise joints by linking bones; overstretching one is a sprain, while a fracture is damage to bone.
Working
- Ligaments join bone to bone.
- A ligament injury is a sprain.
- A fracture would involve a broken bone.
State the conclusion
Working
The description is consistent with a sprain affecting a ligament.
Common misconception 2
Do not swap ligaments and cartilage
Learner response
“Cartilage holds the bones together, while a ligament covers the bone ends to reduce friction.” Correct the two swapped functions.
Correct both structures
View solution step by step
Match each structure to its job
Method
Assign bone-to-bone support to the ligament and the smooth covering to cartilage.
Reason
The two structures help the same joint in different ways.
Working
A ligament joins bone to bone and helps stabilise a joint. Cartilage covers the bone ends, reducing friction and cushioning the joint.
Challenge 3
Use injury and lifestyle evidence
Problem
Case A: a joint is twisted and its ligament is overstretched, but no bone is broken. Case B: a person has low calcium and vitamin D intake and does little physical activity. Identify Case A’s injury and explain two changes that could reduce Case B’s risk of bone problems.
Classify the injury, then link each action to bone health
Hints
Hint 1: case A
An overstretched ligament is not a fracture.
Hint 2: case B
Use both diet and suitable physical activity.
View solution step by step
Use the evidence in both cases
Method
Identify the ligament injury as a sprain, then address both stated lifestyle factors.
Reason
A fracture requires broken bone, while diet and activity can affect the risk of osteoporosis and other bone problems.
Working
Case A is a sprain because the ligament is overstretched and no bone is broken. Case B could include calcium- and vitamin-D-containing foods as part of a balanced diet and take part in suitable regular physical activity. These changes support bone health and can reduce risk, although they do not guarantee prevention.
Guided practice
Try it with support
A joint is inflamed, another has bones displaced, and a third has a torn bone-to-bone band. Name the three conditions or injuries.
Use arthritis, dislocation and sprain once each.
Check the guided answer
Answer: The inflamed or damaged joint has arthritis, displaced bones describe a dislocation, and the torn ligament is a sprain.
Check: A fracture instead means a broken or cracked bone.
Practise and continue
Practise this
Explain how cartilage and ligaments support a joint, then give two ways to reduce bone or joint risk.
Need a hint?
Keep the two structures distinct.
Check your answer
Answer: Cartilage reduces friction at bone ends; ligaments join bone to bone and stabilise the joint. Adequate calcium and vitamin D plus suitable weight-bearing activity can support bone and joint health.
Check: Unsafe excessive loading can itself cause injury.
Think like a scientist
Why does finding an association between inactivity and fracture risk not prove that inactivity is the only cause?
Check the reasoning
Diet, age, existing conditions, medicines, falls and activity type can also affect risk, so controlled evidence and individual assessment are needed.
Remember: A risk factor changes probability rather than guaranteeing an injury.
One-minute check
Hide the page. Explain what cartilage and ligaments do, then distinguish a fracture, sprain and dislocation.
Explain how calcium, vitamin D and suitable activity support bones without guaranteeing that injuries never occur.
Correct this claim: “A sprain must be a broken bone because both can hurt.”
Syllabus and review details
- SEC G1 Science 2027 · 2027
Content structure and syllabus content, PDF pages 8–17
Last reviewed: