The anatomy behind compartment syndromeCompartment syndrome describes the development of high pressure within a muscle compartment. While it most commonly affects the lower leg, it can also affect the arms, thighs, foot, buttocks and the abdomen. It is important to understand that the muscles of the legs are separated into compartments that are enclosed by a connective tissue membrane (called a fascia). This membrane allows very little stretch or expansion as it functions to keep the muscles together and hence functioning efficiently. Alongside muscles, these compartments also contain nerves, blood vessels and connective tissues. The muscles in each compartment have similar functions and typically work together to produce movement. If we look at the lower leg, it is separated into four compartments:
- Anterior compartment
- Lateral compartment
- Superficial posterior compartment
- Deep posterior compartment
What is compartment syndrome?In compartment syndrome, the pressure within a muscle compartment exceeds what is deemed normal. As the compartments are not designed to expand, the muscles, blood vessels and nerves within the compartment and compressed. This impairs circulation and nerve and muscle function, and can cause a large amount of pain for those affected. There are two primary types of compartment syndrome: acute and chronic exertional compartment syndrome, which are categorised by the cause of the increase in pressure. As compartment syndrome can result in insufficient oxygen reaching the tissues and hence tissue death, it is imperative that it is diagnosed and managed promptly and effectively.
What causes compartment syndrome?Acute compartment syndrome typically occurs following trauma or injury that results in bleeding and/or swelling within one of the compartments. These tend to take up more room than is available in the compartment, potentially compressing nerves and blood vessels to the point that they’re unable to perfuse the tissues effectively. Examples of injuries include fractures and muscle bruising, among others. Chronic exertional compartment syndrome affects primarily active individuals, repeatedly occurring following strenuous physical exertion and high-impact activities, such as running. This is as intense activity increases the blood flow to muscle groups and can cause swelling, thereby increasing pressure within the compartment. The result can be pain and impaired muscle function, as well as tightness or cramping in the leg, and neural symptoms such as numbness and tingling.
What are the symptoms?Initially, symptoms of the affected compartment can include:
- Aching / Pain that worsens during exercise
- Tightness and/or cramping
- Numbness, tingling or burning (neural) sensations
- Pain subsides shortly after stopping the activity