A **Thumb Spica Splint** is a specialized orthopedic brace designed to immobilize and support the thumb, often extending to include the wrist. Its primary purpose is to restrict movement of the thumb joint(s), particularly the carpometacarpal (CMC) joint at the base of the thumb and the metacarpophalangeal (MCP) joint. This splint is commonly prescribed for a variety of conditions, including **De Quervain's tenosynovitis, thumb sprains, fractures of the thumb or first metacarpal, arthritis of the thumb, and after thumb surgery**. By holding the thumb in a neutral or slightly abducted position, the splint helps to reduce pain, inflammation, and allows injured tissues to heal by preventing aggravating movements. Thumb spica splints are available in various materials and designs, offering rigid support or softer compression, depending on the specific therapeutic need.