A joint is formed when two or more bones come into contact
Types of joints
Joints are divided into 3 groups according to their degree of movement.
Immovable joints such as the bones of the skull (known as sutures) which are fused.
Partly movable joints have cartilage between them which allows for a small degree of movement e.g.
between the vertebrae also called
cartilaginous joints .
Synovial joints are freely movable and are divided into 4 groups
Hinge joints - e.g elbow and knee joints which allow movement in one plane only
Ball and Sock
et joints - e.g. shoulder and hip joints
allows free movement in almost all directions.
Pivot joint - between atlas and axis vertebrae – allows for turning movement of head
Gliding joints - between ankle bones and wrist bones – allows for rotational movements of
hands and feet
Structure of synovial joint
The joint is completely enclosed in a bag-like joint capsule forming a
synovial cavity.
The joint capsule is lined by a
synovial membrane which secretes
synovial fluid filling the entire cavity thereby
reducing friction
The ends of the bones are covered in
hya l
ine articular cartilage
In addition to the joint capsule, other ligaments are present which attach bones
to each other
