OTC Study Guide 2026

The chemical reaction between plaster of Paris and water is exothermic, meaning it releases heat as it cures. Using water with a temperature greater than 24°C (75°F) dramatically increases the peak temperature of this reaction, significantly raising the risk of causing a thermal burn to the patient's underlying skin.

Secondary intention healing allows a wound to fill with granulation tissue from the bottom up when primary closure is not possible, such as in infected or contaminated wounds.

The head of the fibula, located on the outer side of the leg just below the knee, is where the common peroneal nerve is most superficial. Applying pressure here with traction straps or bandages can lead to nerve compression, resulting in foot drop and sensory deficits. Therefore, this area must be well-padded and the straps applied carefully to avoid this complication.

Classic metaphyseal lesions, also called corner or bucket-handle fractures, are highly specific for non-accidental trauma in infants and young children.

Skeletal traction uses pins or wires placed directly into bone to apply and maintain traction force, unlike skin traction which acts on soft tissue.

A cast saw blade oscillates (vibrates back and forth) rather than spins. The correct and safest technique is to use a firm, plunging motion, pushing the blade through the cast material and then lifting it out before moving to the next adjacent spot. This method prevents the blade from dragging along the skin, which can cause friction burns or lacerations.