The trochoid joint is a type of pivot joint found in the human body. It connects the atlas and axis vertebrae and allows for rotation of the head. The word "trochoid" itself comes from the Greek word "trokhos," meaning wheel. In terms of spelling, "trochoid" is pronounced /ˈtɹɑkɔɪd/ with the stress on the first syllable. The "ch" in "trochoid" is pronounced like a "k" sound, giving it a hard sound. The "oid" ending indicates that it is like or resembling a wheel.
A trochoid joint, also known as a pivot joint, is a type of synovial joint characterized by its rotational movement. It consists of a cylindrical or rounded bone moving within a ring-like structure or socket, allowing primary rotation around a single axis. This joint permits movements like rotation or twisting, without any gliding or sliding actions.
In a trochoid joint, the rounded or oval-shaped part of one bone fits into the concave, ring-like structure of another bone or ligament. This configuration creates a hinge-like pivot point, enabling rotational motion. Examples of trochoid joints can be found in the human body, such as the joint between the head of the radius bone and the ulna bone in the forearm, which allows the rotation of the forearm. Similarly, the joint between the atlas and axis vertebrae in the neck allows the head to rotate from side to side.
Trochoid joints are often surrounded by a synovial capsule that encloses a synovial cavity. This cavity contains synovial fluid, which serves to reduce friction between the moving parts of the joint. Additionally, trochoid joints are reinforced by ligaments that stabilize the joint and prevent excessive rotation.
In summary, a trochoid joint is a type of synovial joint that allows rotational movements around a single axis. It consists of a rounded bone fitting into a ring-like structure or socket, allowing the joint to rotate or twist without sliding or gliding actions.
Pivot j., rotary j.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
The word "trochoid" derives from the Greek word "trokhos" which means "wheel". It refers to a specific type of joint that involves rotational movement resembling the motion of a wheel. The term "trochoid joint" is typically employed in anatomy and describes a joint where one bone rotates within a ring or groove formed by another bone or a connective tissue structure.