Final answer:
A thumb spica splint is commonly used for first metacarpal fractures to properly immobilize the thumb and allow for healing, acknowledging the thumb's unique range of motion and the importance of the carpometacarpal and metacarpophalangeal joints.
Step-by-step explanation:
For first metacarpal fractures, it's common to use a thumb spica splint, which immobilizes the thumb and allows for proper healing. The first metacarpal bone is crucial for thumb mobility and is separate from the rest of the metacarpal bones. This distinction is important because the thumb's range of motion is independent from the other fingers and is essential for tasks such as gripping. It's important to note that while the most commonly fractured carpal bone is the scaphoid, treatment and splinting of metacarpal fractures aim at providing stability for the specific bone involved, in this case, the first metacarpal. The thumb spica splint extends from the forearm down to include the thumb, ensuring immobilization of the carpometacarpal and metacarpophalangeal joints, which are key articulations involved with the first metacarpal and thumb movement.