Joints

Functional Classification of Joints Synarthrosis -- An immovable joint separated by a thin layer of fibrous connective tissue Example: Sutures of the skull

Functional Classification of Joints Amphiarthrosis: Slightly movable joints that are connected by hyaline cartilage or fibrocartilage Example: Ribs to sternum

Functional Classification of Joints Diarthrosis: Freely movable joints Example: Arms and Legs

Structural Classification of Joints Fibrous: Bones are held together by fibrous tissue Example: Sutures of the skull

Structural Classification of Joints Syndesmosomes: The connecting fibers are longer than they are in a suture – The joint has more give than a fibrous joint Example: Distal end of the tibia and fibula

Structural Classification of Joints Cartilaginous Joints: The bone ends are connected by cartilage Example: Intervertebral joints

Structural Classification of Joints Synovial Joints: Articulating bone ends are separated by a cavity with synovial fluid Example: All joints in the limbs

Bursa Sacs Bursa: Flattened fibrous sacs lined with synovial membrane and containing a thin film of synovial fluid Function: Work to reduce friction at joint where rubbing occurs Bursitis: Inflammation of the bursa

Tendon Sheath Tendon Sheath: An elongated bursa that wraps completely around a tendon subjected to friction Function: Protects the tendon from friction

Types of Joints Plane Joint: Articular surfaces are flat Allows only short slipping and gliding type movements Nonaxial: No rotation around an axis Example: Intercarpals (wrist)

Types of Joints (Cont.) Hinge Joint: Cylindrical end of bone fits into a trough shaped surface on another bone Uniaxial: Allow movement in only one axis Example: Elbow joint

Types of Joints (Cont.) Pivot Joint: The rounded end of one bone fits into a sleeve or ring of another bone Uniaxial Example: Proximal radioulnar joint

Types of Joints (Cont.) Condyloid Joint: Egg shaped articular surface of one bone fits into the oval concavity of another Biaxial: Can move side to side and back and forth Example: Tibia Femur joint

Types of Joints (Cont.) Saddle Joints: Each articular surface has both concave and convex areas Biaxial Example: Carpal and metacarpal – Allows you to twiddle thumbs

Types of Joints (Cont.) Ball and Socket: Spherical head of one bone fits into a round socket on the other bone Multiaxial: Allows full range of motion Example: Shoulder and hip

Dislocations Bones in joint become misaligned or displaced

Types of Body Movements Abduction: Move away from midline Adduction: Move toward the midline

Types of Body Movements Flexion: Movement that decreases the angle – Bending—

Types of Body Movements Extension: Increases the angle –Straightening—

Types of Body Movements Rotation: Movement of a bone around a longitudinal axis