Joint Classification

• Joints are classified structurally based on the material that binds the bones together and whether a joint cavity is present.
• Fibrous joints are held together by dense regular connective tissue, lacking a joint cavity.
• Cartilaginous joints have a pad of cartilage between bones, and also lack a joint cavity.
• Synovial joints have articulating bone ends covered with articular cartilage, separated by a joint cavity, enclosed by an articular capsule lined with a synovial membrane, and containing synovial fluid.

Fibrous Joints

• Gomphosis: Immobile joint (synarthrosis) where tooth is held to the jaw by periodontal ligaments.
• Suture: Immobile joint (synarthrosis) where skull bones are connected by dense regular connective tissue, such as the lambdoid suture that connects the occipital and parietal bones.
• Syndesmosis: Slightly mobile joint (amphiarthrosis) where bones are connected by dense regular connective tissue fibers (interosseous membrane), such as the articulation between the radius and ulna or the tibia and fibula.

Cartilaginous Joints

• Synchondrosis: Immobile joint (synarthrosis) where bones are connected by hyaline cartilage, such as epiphyseal plates in growing bones and costochondral joints.
• Symphysis: Slightly mobile joint (amphiarthrosis) where bones are connected by fibrocartilage, such as the pubic symphysis and intervertebral disc articulations.

Synovial Joints

• Synovial joints are all freely mobile (diarthrosis).
• Plane joint: Flattened or slightly curved faces slide across one another, examples include intercarpal and intertarsal joints.
• Hinge joint: Convex feature of one bone fits into a concave depression of another bone, examples include elbow, knee, and IP (interphalangeal) joints.
• Pivot joint: Bone with a rounded surface fits into a ring formed by a ligament and another bone, example is the atlantoaxial joint.
• Condylar joint: Oval articular surface on one bone interfaces with a depressed oval surface on another bone, examples include MP (metacarpophalangeal or metatarsophalangeal) joints.
• Saddle joint: Saddle-shaped articular surface on one bone interfaces with a saddle-shaped surface on another bone, example is the articulation between carpal and first metacarpal bone.
• Ball-and-socket joint: Round head of one bone rests within cup-shaped depression in another bone, examples include the glenohumeral joint and hip joint.