soikeanivelinä

soikeanivelinä is a Finnish term that translates to "oval joints" or "ellipsoidal joints" in English. This refers to a type of synovial joint in anatomy where the oval-shaped articular surface of one bone fits into the complementary elliptical cavity of another bone. This structure allows for a wide range of motion, primarily biaxial movement, meaning it can move in two planes.

These joints permit flexion and extension (bending and straightening) as well as abduction and adduction (moving away from and towards the midline of the body). Circumduction, a movement that combines these four actions to create a circular motion, is also possible. However, rotation around an axis is generally not a primary function of soikeanivelinä.

Examples of soikeanivelinä in the human body include the radiocarpal joint (the wrist joint), where the distal end of the radius articulates with the carpal bones, and the metacarpophalangeal joints (knuckles), where the metacarpal bones connect with the phalanges (finger bones). The movements at these joints are crucial for many daily activities, from grasping objects to writing. The articular surfaces are covered with hyaline cartilage to reduce friction and absorb shock, and the joint is enclosed within a capsule filled with synovial fluid for lubrication.