Bouchard's nodes are hard, bony outgrowths or gelatinous cyst

Cyst

A cyst is a closed sac, having a distinct membrane and division on the nearby tissue. It may contain air, fluids, or semi-solid material. A collection of pus is called an abscess, not a cyst. Once formed, a cyst could go away on its own or may have to be removed through surgery.- Locations :* Acne...

s on the proximal interphalangeal joints (the middle joints of fingers or toes.) They are a sign of osteoarthritis

Osteoarthritis

Osteoarthritis also known as degenerative arthritis or degenerative joint disease, is a group of mechanical abnormalities involving degradation of joints, including articular cartilage and subchondral bone. Symptoms may include joint pain, tenderness, stiffness, locking, and sometimes an effusion...

, and are caused by formation of calcific

Calcification

Calcification is the process in which calcium salts build up in soft tissue, causing it to harden. Calcifications may be classified on whether there is mineral balance or not, and the location of the calcification.-Causes:...

 spurs

Bone spur

Osteophytes, commonly referred to as bone spurs, are bony projections that form along joint margins. They should not be confused with enthesophytes, which are bony projections which form at the attachment of a tendon or ligament.-Pathophysiology:...

 of the articular (joint) cartilage

Cartilage

Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...

.

Bouchard's nodes are comparable in presentation to Heberden's node

Heberden's node

Heberden's nodes are hard or bony swellings that can develop in the distal interphalangeal joints...

s, similar osteoarthritic growths on the distal interphalangeal joint

Distal interphalangeal joint

Distal interphalangeal joint can refer to:* Interphalangeal articulations of hand* Interphalangeal articulations of foot...

s, but are significantly less common.

Eponym

Bouchard's nodes are named after French pathologist Charles-Joseph Bouchard

Charles-Joseph Bouchard

Charles-Joseph Bouchard was a French pathologist born in Montier-en-Der, a commune the department of Haute-Marne. He studied medicine in Lyon and Paris, where he obtained his doctorate in 1866. In 1874 he became a physician at Bicêtre Hospital, and in 1879 was appointed chair of general pathology...

 (1837-1915).
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External links

• Diagram of Heberden's and Bouchard's nodes at WebMD
  WebMD
  WebMD is an American corporation which provides health information services. It was founded in 1996 by Jim Clark and Pavan Nigam as Healthscape, later Healtheon, and then acquired WebMD in 1999 to form Healtheon/WebMD...