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A plane joint (arthrodial joint, gliding joint, plane articulation) is a synovial joint which, under physiological conditions, allows only gliding movement. Plane joints permit sliding movements in the plane of articular surfaces. The opposed surfaces of the bones are flat or almost flat, with movement limited by their tight joint capsules.
The inner lining of the joint consists of the synovium (also called the synovial membrane), a thin layer located between the joint capsule and the joint cavity. The word "synovium" is derived from the word "synovia" (or synovial fluid ), which is a clear, viscous fluid produced by the synovium, and its main purpose is to reduce friction between ...
This joint unites long bones and permits free bone movement and greater mobility. [1] The synovial cavity/joint is filled with synovial fluid. The joint capsule is made up of an outer layer of fibrous membrane, which keeps the bones together structurally, and an inner layer, the synovial membrane, which seals in the synovial fluid.
The fibroblast-like synoviocytes (derived from mesenchyme) [3] manufacture a long-chain sugar polymer called hyaluronan (hence rich in endoplasmic reticulum); which makes the synovial fluid "ropy"-like egg-white, together with a molecule called lubricin, which lubricates the joint surfaces. The water of synovial fluid is not secreted as such ...
The acromioclavicular joint provides the ability to raise the arm above the head. This joint functions as a pivot point (although technically it is a gliding synovial joint), acting like a strut to help with movement of the scapula resulting in a greater degree of arm rotation.
The shoulder joint involves articulation between the glenoid cavity of the scapula (shoulder blade) and the head of the upper arm bone and functions as a diarthrosis and multiaxial joint. Due to the very loose joint capsule that gives a limited interface of the humerus and scapula, it is the most mobile joint of the human body.
Cells at the center of this interzone region undergo cell death to form the joint cavity, while surrounding mesenchyme cells will form the articular capsule and supporting ligaments. The process of endochondral ossification, which converts the cartilage models into bone, begins by the twelfth week of embryonic development.
The connection between a tooth and the jawbone is also called a joint, and is described as a fibrous joint known as a gomphosis. Joints are classified both structurally and functionally. [4] Joints play a vital role in the human body, contributing to movement, stability, and overall function.