A splint is an orthopedic device used to support and stabilize an injured part of the body, primarily to reduce pain and prevent further damage. Splints are often used for acute injuries like sprains, dislocations, or fractures until definitive treatment can be administered. Unlike a cast, which completely encircles the limb and is non-adjustable, a splint is non-circumferential. This design allows it to accommodate the natural swelling that occurs immediately following an injury without compromising circulation, making splints a safer initial choice when significant tissue swelling is anticipated.
Rigid Immobilization Devices
Rigid splints are constructed from hard, unyielding materials for injuries that require complete immobilization. These devices are typically fabricated from plaster, fiberglass, aluminum, or pre-formed plastic, often secured with elastic bandages or straps. Their purpose is to prevent movement at and around the injury site, which is important for stabilizing acute fractures or reduced joint dislocations.
A common example, the sugar tong splint, is shaped like a horseshoe and applied to the forearm and elbow to prevent movement at the wrist and rotation of the forearm. By immobilizing the joints above and below the injury, these rigid supports keep bone fragments in alignment. The firm structure counteracts forces that could displace the injury, offering strong initial support before a full cast is applied or surgery is performed.
Soft and Flexible Supports
Soft and flexible supports prioritize patient comfort and limited motion for less severe injuries. These splints incorporate pliable materials such as foam, felt, elastic wraps, or padded cloth to provide gentle support. They are frequently used for minor injuries like mild sprains, muscle strains, or for conditions where full immobilization is not necessary.
A soft cervical collar, for instance, is made of foam and fabric and does not completely restrict neck movement; rather, it offers a reminder to the wearer to limit voluntary motion. Specialized soft supports, such as a pillow splint, may be used to provide comfortable elevation for an injured ankle or foot. These less restrictive options are often chosen for long-term use or during the final stages of recovery where some movement is beneficial for joint mobility.
Traction Devices
Traction splints are a specialized category designed to apply a continuous, longitudinal pulling force to an injured limb. These are used almost exclusively for mid-shaft femur fractures, where the powerful surrounding thigh muscles contract and cause the broken bone ends to overlap and shorten the limb. The resulting muscle spasm is a major source of pain and can increase internal bleeding.
Devices like the Sager or Hare traction splints work by anchoring against the pelvis or groin and using an ankle hitch to apply gentle, sustained tension. This pulling force overcomes the muscle spasm, helping to realign the bone fragments and restore the limb’s approximate anatomical length. By reducing the overlap and stabilizing the fracture, the splint significantly decreases pain and limits the potential for further soft tissue or vascular injury.
Air and Vacuum Splints
Air and vacuum splints employ unique mechanisms of pressure or suction to achieve stabilization. An air splint is a double-layered plastic sleeve that is inflated once placed around the injured limb, providing stabilization through uniform external compression. While easy to apply, these devices are sensitive to changes in temperature or altitude, and over-inflation presents a risk of reducing blood flow or causing acute compartment syndrome.
Vacuum splints use a different principle, consisting of a durable envelope filled with polystyrene beads. After the splint is positioned around the injured limb, a pump evacuates the air. This causes atmospheric pressure to push the walls inward, forcing the beads to lock together and create a rigid, custom-molded cast. This mechanism is particularly effective for stabilizing joints with complex or irregular shapes, such as the elbow or shoulder.