The joint system is formed by the joints, which can be defined as the region of union between two or more bones. All bones in the body, with the exception of the hyoid bone, are articulated with at least one other bone.
→ Joint Functions
The joints, also called joints, have two main functions: to keep the bones together and to allow the movement of the bone. skeleton. Thanks to the presence of the joints, we have a stable body that can, for example, maintain an erect posture. In addition to ensuring the union of the skeleton, the joints also prevent bone wear.
→ Classification of joints
There are different ways to classify a joint, the most common being the classification that uses the material found between the bones as a criterion. According to this criterion, we can divide them into:
- Fibrous joint - Also called synarthrosis or immobile joint, it has a small separation with fibrous connective tissue between the bones. Its main role is to provide shock absorption.
The fibrous joint can be classified into two types: sutures and syndesmoses. At
sutures are those joints found in the bones of the skull. already the syndesmosis is the one found between the tibia and fibula.- Cartilaginous joint - Also called amphiarthrosis or semi-mobile joint, it has cartilaginous tissue between the bones, which can be of the hyaline or fibrous type. When the cartilage is hyaline, the joint is called synchondrosis and, when the cartilage is fibrous, it is called symphysis. Cartilaginous joints are found in the hip bones and between the vertebrae.
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- Synovial articulation - In this joint, also called diarthrosis or mobile, there is free sliding between the surface of one bone and another due to the presence of a fluid called synovial. Unlike other forms of articulation, the articulated pieces are joined through the articular capsule, where the fluid is located.
It is noteworthy that synovial joints can be classified according to their ability to move. If they move on only one axis of rotation, they are called uniaxials; if they have two axes, they are called biaxial; and if they have three axes, they are called polyaxials.
Synovial joints move in a variety of ways. Among the movements performed by this type of joint, we can mention flexion, extension, abduction, adduction, rotation, pronation, inversion, refraction, elevation and depression.
→ Diseases that affect the joints
There are several diseases that can affect the joints. Among them, we can mention:
Bursitis:Inflammation of the synovial bursa, also called a bursa.
Rheumatoid arthritis: Inflammation of joints and associated structures.
Drop: A type of arthritis characterized by the deposit of uric acid crystals in the joint.
Rheumatic fever:Inflammation of synovial tissues, tendons and other connective tissues around the joints.
By Ma. Vanessa dos Santos
Would you like to reference this text in a school or academic work? Look:
SANTOS, Vanessa Sardinha dos. "Joints"; Brazil School. Available in: https://brasilescola.uol.com.br/biologia/articulacoes.htm. Accessed on June 27, 2021.
