Design a Finger Splint
A small, real design problem behind every orthopedic device — immobilize a joint without cutting off circulation or comfort.
Related field: Biomedical Engineering
Mission Briefing
Objective
Design a splint that keeps one finger joint from bending, while staying comfortable enough to wear for several minutes.
Constraints
- Only cardboard, popsicle sticks, tape, and soft fabric or cotton padding are allowed
- It must not be wrapped so tight that it noticeably restricts blood flow — check for color or numbness and loosen it if you notice either
- It has to actually stop the joint from bending, not just make it harder
Concept You're Testing
Immobilization and pressure distribution — the same core problem behind real orthopedic splints and braces: restrict motion at a joint without concentrating pressure on one spot or cutting off circulation.
What You'll Need
- A few popsicle sticks or a strip of stiff cardboard
- Soft fabric, cotton balls, or a paper towel for padding
- Tape or a rubber band
- A willing finger to test on
Instructions
- 1Pick one finger joint (like the middle knuckle) as your target — the splint needs to stop that specific joint from bending.
- 2Cut a popsicle stick or cardboard strip long enough to span past the joint on both sides.
- 3Add a layer of soft padding between the rigid material and the skin — this is what protects comfort and circulation.
- 4Wrap tape or a rubber band around the assembly to hold it in place, snug but not tight.
- 5Try to bend the joint. It should resist bending significantly compared to without the splint.
- 6Wear it for 2–3 minutes and check the fingertip for color changes or numbness — loosen immediately if you notice either.
- 7Adjust your design based on what you found, and test again.
How to Measure Results
Compare how many degrees the joint can still bend with the splint on versus without it (even a rough visual comparison works), and note whether circulation stayed normal during the wear test.
Skills You'll Practice
- Why medical devices have to balance function (restricting motion) against comfort and safety (circulation, pressure points)
- Iterative design — the first version rarely gets the balance right on the first try
- Basic anatomy awareness — where a joint actually bends and what needs to be immobilized
- Testing a design on a real, non-idealized subject (an actual hand, not a flat surface)
If It Doesn't Work the First Time
That's normal — this challenge follows the same design process real engineers use. A failed test just tells you where to go back and improve.
Figure out what problem you're actually solving, and what would even count as success. Skip this step and jump straight to building, and a lot of bad designs happen right here.