Classification of Joints
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Joints are places where two or more bones meet. They are classified based on their structure and the type of movement they allow.
CLASSIFICATION
OF JOINTS
Joints are classified structurally and
functionally. Structurally:
- Fibrous
joints (synarthroses)
- bones joined by fibrous tissue; little or no movement.
- Cartilaginous
joints (amphiarthroses)
- bones joined by cartilage; limited movement.
- Synovial
joints (diarthroses) -
freely movable joints with a synovial cavity.
FIBROUS JOINTS (SYNARTHROSES)
- Immovable
or very limited movement.
- Examples:
sutures of the skull, gomphosis (tooth in socket).
CARTILAGINOUS JOINTS (AMPHIARTHROSES)
- Bones
united by hyaline cartilage or fibrocartilage.
- Examples:
intervertebral discs (fibrocartilage), pubic symphysis;
allow limited movement and absorb shock.
SYNOVIAL JOINTS (DIARTHROSES)
Freely movable joints with common features:
- Articular
surfaces covered by hyaline (articular) cartilage.
- Bones
held together by ligaments.
- Enclosed
by a fibrous capsule lined internally by a synovial membrane.
- Joint
cavity contains synovial fluid for lubrication.
Types of Synovial Joints and Examples
|
JOINT TYPE |
DESCRIPTION |
EXAMPLES |
|
Plane (gliding) |
Flat articular surfaces that glide |
Intercarpal, intertarsal joints |
|
Hinge |
Movement in one plane (flexion/extension) |
Elbow, interphalangeal joints |
|
Pivot |
Rotation around a central axis |
Proximal radioulnar joint (head of radius
on ulna), atlas-axis |
|
Ball-and-socket |
Spherical head in cup-like socket;
movement in many axes |
Shoulder (glenohumeral), Hip |
|
Condyloid (ellipsoid) |
Oval condyle fits into elliptical cavity;
movement in two planes |
Wrist (radiocarpal), metacarpophalangeal
joints |
|
Saddle |
Articulating surfaces both concave and
convex; wide range of motion |
Carpometacarpal joint of thumb |
