Joints – Classification

Define Joint.

 Joint (articulation) is a junction between two or more bones.

What are the Functions of Joints?

 Functions of joints are:

•  They allow movement
• They allow growth
•  They allow moulding of head during childbirth.
• They allow transmission of forces.

Classify Joints.

Joints can be classified on the basis of function or structure.

Structural classification is based on:

o Material that binds bones together.
o Presence or absence of a joint cavity.

Classify Joints According to Structure.

 Fibrous joints

• Bones are connected by fibrous connective tissue.
• Do not have a joint cavity.
• Most are immovable or only slightly movable.

Cartilaginous joints

• Bones are united by cartilage.
• Most are slightly movable.
• Lack a joint cavity.

Synovial joints

• Joint cavity is present between the bones, and the joint is surrounded by articular capsule.
• Most movable type of joint.
• Most are “simple” and have just two articulating surfaces.
• Some are “compound” with more than two articulating surfaces (e.g. elbow (humerus, radius and ulna) and knee (femur, tibia, fibula, patella) joints).

Claasify Joint on the Basis of Function.

Functional classification is based on  degree of mobility. 

• Synarthroses (immovable): common in axial skeleton (Fibrous joints – sutures).
• Amphiarthroses (slightly movable):common in axial skeleton ( secondary cartilaginous joints) .
• Diarthroses (freely movable): common in appendicular skeleton (synovial joints).