The joints of the appendicular skeleton allow movement between bones while connecting them together. Joints are classified based on their structure and function. Structural classifications include fibrous, cartilaginous, and synovial joints. Functional classifications include synarthroses, amphiarthroses, and diarthroses based on their range of motion. Synovial joints have the greatest range of motion and include features like articular cartilage, a joint capsule, and ligaments. The shape of synovial joints determines the specific movements they allow, such as hinge, pivot, ball-and-socket, and others.

1. AppendicularSkeleton The Joints

2. TheJoints Joints serve to hold the bones together but allow movement at the same time Joints are classified by structure and function Structural refers to tissues found in the joint Fibrous Cartilaginous Synovial Functional refers to the amount of movement allowed Synarthroses – no movement allowed Amphiarthroses – slightly movable Diarthroses – freely movable

3. TheJoints Fibrous Joints Fibrous tissue connects bones together at site of articulation Usually associated with immovable, or synarthroses, joints (ex. the sutures of the skull) Cartilaginous Joints Joints that include bones separated by cartilage tissue Usually amphiarthrotic (ex. intervertebral joints) or synarthrotic (ex. epiphyseal plates)

4. TheJoints

5. TheJoints Synovial Joints Will include cartilage, but also have a joint cavity between bone ends All synovial joints have four features: Articular cartilage – covers the ends of bones Fibrous articular capsule – joint surfaces enclosed by capsule of fibrous connective tissue that is lined by a synovial membrane Joint cavity – the area enclosed by the capsule, contains synovial fluid Reinforcing ligaments – capsule is reinforced/held in place by ligaments

6. TheJoints

7. TheJoints Movement of synovial joints is determined by their shape Plane Joint – articular surfaces are flat and allow minimal slipping or gliding movement (ex. intercarpal joints) Hinge Joint – cylindrical shape of one end with the other end fitting around it allows the bones to only move around one axis (ex. elbow, between phalanges) Pivot Joint – round end fits into a complimentary end of another bone, only moves around one axis (ex. radioulnar joint)

8. TheJoints Condyloid Joint – slightly rounded end fits into a shallow concavity of articulating bone, allows movement from side to side and back and forth, but no rotation (ex. knuckles) Saddle Joint – each surface has a convex and concave area resembling a saddle, allows exaggerated condyloid movement (ex. #1 metacarpal and carpal joint) Ball-and-socket Joint – rounded head of one bone fits into the socket of the other bone, allows side to side, back and forth, and rotation movements (ex. shoulder and hip)

9. TheJoints