The Articular System

1. Gliding joints

• Articular surfaces are essentially flat
• Allow only slipping or gliding movements
• Only examples of nonaxial joints
• E.g. intercarpal/intertarsal joints, vertebral articular processes

Hinge joints

• Cylindrical projections of one bone fits into a trough-shaped surface on another
• Motion is along a single plane (like a mechanical hinge)
• Uniaxial joints permit flexion and extension only
• Examples: elbow and interphalangeal joints

Pivot Joints

• Rounded end of one bone protrudes into a “sleeve,” or ring, composed of bone (and possibly ligaments) of another
• uniaxial rotation of one bone around its own long axis
• Examples: “No” motion of the head via joint between the the 2nd and 3rd vertebra

Condyloid or Ellipsoidal Joints

• Oval articular surface of one bone fits into a complementary depression in another
• Both articular surfaces are oval Biaxial joints permit all angular motions
• Examples: radiocarpal (wrist) joints, and metacarpophalangeal (knuckle) joints

Saddle Joints

• Similar to condyloid joints but allow greater movement
• Each articular surface has both a concave and a convex surface
• Example: carpometacarpal joint of the thumb

Ball-and-Socket Joints

• A spherical or hemispherical head of one bone articulates with a cuplike socket of another
• Multiaxial joints permit the most freely moving synovial joints
• Examples: shoulder and hip joints