Types of Joints

Articular System – series of joints that allow movement Arthrology – study of joints Joint Articulation – the connecting point of two bones Two functions: allow motion and provide stability

Name of the joints typically are a combination of the bones connected Articulation can be: Freely movable such as knee or hip AKA: Synovial Joints and Diarthrosis Slightly movable such as ribs to sternum AKA: Cartilaginous Joints and Amphiarthroses Immovable such as the skull AKA: Fibrous Joints and synarthroses Name of the joints typically are a combination of the bones connected Ex. Sternoclavicular jont (sternum and clavicle)

Fibrous Joints Immobile Held closely together and only separated by fibrous connective tissue Bones very close contact

3 Types of Fibrous Joints  Sutures 3 Types of Fibrous Joints  Sutures * thin layer of fibrous tissue unites bones * fuse completely by adulthood * only found in skull  Syndesmosis * slightly movable, connected by ligaments Ex: radius and ulna move as one  Gomphosis * fits in a socket, held by ligaments Ex: tooth in the alveolus socket

Cartilaginous Joints Slightly movable Bones are connected by fibrocartilage (specialized connective tissue with thick fibers) Example: Ribs to the sternum

Synovial Joints Move freely Ends of bones are covered by articular cartilage Separated by a joint cavity Most frequently injured Grouped in how they work

Components of joint enclosed in a joint capsule Outer layer – ligaments holds bones together Inner layer – synovial membrane produces synovial fluid

Synovial fluid: colorless, contains salts, fats, and other substances Provides lubrication Acts as a shock absorber and cushion between bones

Bursa – sac full of synovial fluid, reduces the friction between tendons, ligaments, & bones Meniscus – cartilaginous disc surrounded with fluid to reduce friction during movement and adds stability

Pivot Joint Bones that move around a central axis Creates a rotational movement

Gliding Joint Bones make a sliding motion Move back & forth or side to side

Hinge Joint One bone has a convex surface which fits into a concave surface on the other bone

Ellipsoidal (Condyloid) Joint Bones can move in many directions but can not rotate

Ball & Socket Joint One bone has rounded end that ends into a concave (socket) of another bone Widest range of movement

Saddle Joint Two bones with complementary shape, both have concave and convex regions