What is the primary purpose of a cast?

• A. Provide cushion
• B. Restore joint flexibility quickly
• C. Immobilize the joint to allow fracture healing
• D. Promote skin moisture

Answer: (C)

The main idea here is immobilization. A cast is used to keep the fractured bones and surrounding joints still, which prevents movement at the injury site and helps the bones stay properly aligned as they heal. When movement occurs, it can disrupt the natural healing process, slow the formation of the new bone, and increase pain or risk of displacement. By stabilizing the area, the cast provides a protected environment for the body to form a stable callus and resume normal structure over time.

Padding inside a cast may help cushion bony prominences and protect the skin, but that isn’t its primary purpose. Restoring joint flexibility quickly isn’t the goal—movement is limited during healing and flexibility is regained later through rehabilitation. Promoting skin moisture isn’t a function of immobilization, either.