Condyloidellipsoid

Condyloidellipsoid is a term used in anatomy to describe a class of synovial joints, often treated interchangeably as condyloid or ellipsoidal joints. These joints feature an oval-shaped convex articular surface on one bone that fits into a reciprocal elliptical concavity on the adjacent bone, together bounded by a joint capsule and synovial membrane.

Movement at condyloidellipsoid joints is typically biaxial. The primary motions are flexion and extension (along one axis) and abduction and adduction (along a perpendicular axis), with the possibility of circumduction. Rotation about the long axis of the bones is generally limited or not present, depending on the specific joint and its supporting ligaments.

Common examples include the radiocarpal joint of the wrist, where the distal radius and adjacent carpal bones form the ellipsoid articulation, and the metacarpophalangeal joints (knuckles) of the fingers. The thumb’s carpometacarpal joint is sometimes described as saddle-shaped, a related but distinct type of biaxial joint, whereas other joints in the hand may be categorized as condyloid/ellipsoidal.

In contrast to uniaxial hinge joints (such as the elbow) and multiaxial ball-and-socket joints (such as the shoulder), condyloidellipsoid joints provide a balance of movement and stability suitable for varied hand and wrist functions. Some authors distinguish ellipsoid from saddle joints instead of using them interchangeably, reflecting subtle differences in articular geometry and range of motion.

Clinically, these joints can be affected by conditions such as osteoarthritis, rheumatoid arthritis, and ligament injuries, which may limit motion or cause pain and instability.