What are Joints? Joints occur where bones meet. They not only hold together but also give it the mobility to the skeleton. Joints are classified either on the basis of the amount of movement or on the basis of structure. Let’s discuss in detail what are joints and classification of joints are as under;
CLASSIFICATION OF JOINTS
CLASSIFICATION OF JOINTS ON THE BASIS OF THE AMOUNT OF MOVEMENT
Joints are classified on the basis of the amount of movement allowed by them, into three categories:
i) Immovable joints
ii) Slightly Movable Joints
iii) Freely Movable Joints
The freely movable joints are of two types viz, Hinge joint and ball and socket joint.
CLASSIFICATION OF JOINTS ON THE BASIS OF STRUCTURE
Joints are also classified on the basis of structure:
1. Fibrous Joints
These joints are held together by short fibers embedded in connective tissue. Such joints are present in the skull, which fix teeth into jaws,
2. Cartilaginous Joints
These joints allow little or no movement. Hyaline cartilage forms a joint between growing bones. The bones held together by fibrous cartilage were found between vertebrae at the point where coxal bones meet in front of the pelvis.
3. Synovial Joints
These joints contain a cavity filled with fluid and are adapted to reduce friction between the moving joints. The joint is surrounded by a layer of connective tissue called fibrous capsule” and their inner layer synovial membrane. Some parts of a capsule may be modified to form distinct “Ligament” holding the bones together. Based on structure and movements allowed, the synovial joints can be classified further into major categories hinge joint and ball and socket joint.
i. Hinge Joint
The joint that allows the movements in two directions is called hinge joint. These are at elbow and knee. At these joints, pairs of muscles are arranged in the same plane as that of joints. One end of each muscle, the origin is fixed to the immovable bone on one side of a joint and the other end of muscles, the insertion is attached to the far side of the joint.
ii. Ball & Socket Joint
These joints allow the movement in several directions. Such joints have at least two pairs of muscles present perpendicular to each other. They provide maximum flexibility. Hip joint and shoulder joint are the examples of ball and socket joints.