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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.
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 inner layer is mainly composed of two cell types, specialized macrophages (macrophage-like synovial cells) and fibroblast-like synoviocytes, which are important in maintaining the internal joint homeostasis. These cells represent the main source of hyaluronic acid and also other glycoproteins, major components of the synovial fluid. [1] [2]
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.
When referring to bone, or in this case cartilage, the originally undifferentiated mesenchymal stem cells lose their pluripotency, proliferate and crowd together in a dense aggregate of chondrogenic cells (cartilage) at the location of chondrification. These chondrogenic cells differentiate into so-called chondroblasts, which then synthesize ...
The joint locks (or rather becomes close packed) on one side as weight is transferred from one leg to the other, and through the pelvis the body weight is transmitted from the sacrum to the hip bone. The motions of the sacroiliac joint Anterior innominate tilt of both hip bones on the sacrum (where the left and right move as a unit)
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.