Synonyms
Leg, synovial cyst, ganglion cyst further meaning: In medical terminology, “ganglion” is also an anatomical term for an accumulation of nerve cell bodies. This will not be discussed in this article.
Introduction
A ganglion is a fluid-filled protuberance of the synovial membrane that often occurs in the area of the wrist. Because it presents as a solid, usually painless swelling that looks similar to a protruding bony prominence, the ganglion is also known as an overhanging leg in layman’s language. Medically, the ganglion is also called a pseudotumor because of its similarity to a tumor, although it is actually a cyst, i.e. a fluid-filled cavity. In most cases, a ganglion is harmless and does not require treatment. Removal by surgery is only necessary if symptoms occur – for example, because the ganglion presses on nerves or blood vessels.
Causes: How does a ganglion develop?
All joints of the body are surrounded by a joint capsule, which consists of connective tissue and is filled with a clear fluid (synovia). This stabilizes the joint on the one hand and on the other hand the synovial fluid, as a sliding layer, prevents the joint cartilages from rubbing directly against each other. If the joint is irritated, e.g. by overloading or arthrosis, excessive production of synovial fluid can occur.
This creates excess pressure in the joint. If there is now a general weakness of the connective tissue or if the joint capsule is overstretched due to a previous injury, the joint skin can protrude. A cavity is then formed which is connected to the joint space and filled with synovial fluid. Depending on the amount of fluid it contains, the size of the ganglion can change under certain circumstances – in most cases it increases when the joint is moved. In rare cases, the joint skin bulges inwards instead of outwards, resulting in a ganglion in the joint space (intraosseous ganglion).
Symptoms of a ganglion
Often, patients with a ganglion have no complaints, as it is usually not painful. In some cases, however, pressure sensitivity may exist because there are pain receptors in the joint capsule that can be activated when the ganglion is irritated or grows. Since ganglia can reach a size of more than eight centimeters, the mobility of the joint can sometimes be limited.
In most cases, however, patients only experience symptoms when the ganglion presses on nerves or blood vessels in its vicinity. Then pain, numbness, tingling or muscle weakness may occur at the affected area. If a ganglion grows in the area of a tendon, painful tendosynovitis can also occur.
Most ganglions cause no pain and hardly any other discomfort. However, depending on its size and anatomical location, a ganglion can cause pain of varying intensity. For example, a large ganglion can impair the mobility of muscles and joints and cause pain that depends on movement.
At the same time, leaning on the ganglion can cause severe pain. If a ganglion presses on a tendon, it can cause painful tendosynovitis and, if a nerve is pinched, paresthesia can cause pain. In addition, even very small ganglions can cause pain.
Occasionally, tiny ganglions can occur that are located deeper under the skin and are only noticeable as pain. Such ganglia are often diagnosed late or not at all. The pain can have different pain characteristics depending on where they are located, how large they are and what kind of structures they press on.
Depending on where the ganglion is anatomically located, it can cause different symptoms. Larger ganglions can also press on a nerve in addition to vessels and tendons. If a large ganglion presses on a nerve, unpleasant complaints can arise. Those affected can experience unpleasant symptoms such as tingling, formication or numbness in the area supplied by the nerve.
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