• Medical Author:
    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

  • Medical Editor: Jerry R. Balentine, DO, FACEP
    Jerry R. Balentine, DO, FACEP

    Jerry R. Balentine, DO, FACEP

    Dr. Balentine received his undergraduate degree from McDaniel College in Westminster, Maryland. He attended medical school at the Philadelphia College of Osteopathic Medicine graduating in1983. He completed his internship at St. Joseph's Hospital in Philadelphia and his Emergency Medicine residency at Lincoln Medical and Mental Health Center in the Bronx, where he served as chief resident.

Read about the causes and types of cysts.

Cyst Symptoms and Causes

A cyst is a closed sac- or bladder-like structure that is not a normal part of the tissue where it is found. Cysts are common and can occur anywhere in the body in persons of any age. Cysts usually contain a gaseous, liquid, or semisolid substance. Cysts vary in size; they may be detectable only under a microscope or they can grow so large that they displace normal organs and tissues. The outer wall of a cyst is called the capsule.

Cysts can arise through a variety of processes in the body, including...

What is a ganglion?

A ganglion is a sac-like swelling or cyst formed from the tissue that lines a joint or tendon. The tissue, called synovium, normally functions to produce lubricating fluid for these areas. A ganglion is a cyst formed by the synovium that is filled with a thick jelly-like fluid. While ganglia can follow local trauma to the tendon or joint, they usually form for unknown reasons. Occasionally, ganglia are early signs of arthritis that will become more obvious in the future.

What are ganglion causes and risk factors?

Ganglions can be caused by inflammation of the tissue lining joints and tendons. This inflammation can be a result of local injury or underlying arthritis.

Where do ganglia form and what symptoms do they cause?

Ganglia can form around any joint, but they are most frequently found in the wrist and ankles. They are usually painless and often barely visible as localized swellings. They typically do not appear to be inflamed. The largest ganglions form behind the back of the knee, causing a sense of fullness or tightness. A ganglion here is referred to as a Baker cyst, after the doctor who originally described the condition.

What specialists treat a ganglion?

Specialists who treat ganglions include primary-care providers such as general medicine doctors, family medicine doctors, and internists, as well as rheumatologists and general and orthopedic surgeons.

How do doctors diagnose and assess a ganglion?

Doctors diagnose a ganglion by physical examination. These ganglions can usually be felt on examination. A ganglion can be a result of underlying arthritis of the adjacent joint, and X-ray analysis is often used to determine the integrity of joints affected.

Medically Reviewed by a Doctor on 8/23/2016

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