Prehospital Trauma Life Support (PHTLS) Practice Test

What is the best description of a "compartment syndrome" as it relates to trauma?

1. Excessive fluid accumulation in body cavities

2. Increased pressure within a muscle compartment

3. Swelling that impairs circulation

4. Bone fragments breaking through the skin

The correct answer is: Increased pressure within a muscle compartment

Compartment syndrome is characterized by increased pressure within a muscle compartment, which can lead to severe muscle and nerve damage if not addressed promptly. Each muscle compartment is surrounded by a tough membrane called fascia, which does not stretch. When swelling occurs due to trauma, bleeding, or excessive fluid accumulation within this confined space, the pressure rises. This elevated pressure compromises blood flow and can result in ischemia, potentially leading to irreversible damage to the muscles and nerves within the compartment. The other responses relate to different physiological events or conditions but do not accurately capture the essence of compartment syndrome. For instance, while swelling that impairs circulation can occur in many contexts, it does not specifically describe the confined pressure build-up characteristic of compartment syndrome. Similarly, excessive fluid accumulation can happen within body cavities but does not pertain to the defined fascial compartments in the context of muscle and nerve function. Lastly, bone fragments breaking through the skin describes an open fracture rather than the pressure dynamics associated with compartment syndrome. Thus, the definition encompassing increased pressure within a muscle compartment is the most accurate descriptor of this critical condition.