Joints and Movement
Classes of Joints:
Fibrous Joints: No joint cavity and little to no movement.
Specific Joints:
Sutures: Interdigitate opposing skull bones, may ossify in adults (synostosis).
Fontanels: Flexible areas in infants allowing growth.
Synovial Joints: Complex joints with a joint cavity containing synovial fluid.
Characteristics: Allow a wide range of movement and have accessory structures like bursae (reduce friction) and ligaments (stabilize joints).
Types of Synovial Joints:
Plane: Uniaxial (e.g., intervertebral joints).
Saddle: Biaxial (e.g., carpometacarpal joint of the thumb).
Hinge: Uniaxial (e.g., elbow, knee).
Pivot: Uniaxial rotation (e.g., atlantoaxial joint).
Ball-and-socket: Multiaxial (e.g., shoulder, hip).
Ellipsoid: Biaxial limited movement (e.g., radiocarpal joint).
Movement Types: Gliding, angular (flexion/extension), and circular movements such as rotation and circumduction.
Temporomandibular Joint (TMJ): Combination of plane and ellipsoid with fibrocartilage disk allowing various movements such as depression/elevation.
Clinical Impact: TMJ Disorders affect jaw function.
Shoulder Joint (Glenohumeral): Ball-and-socket joint supported by rotator cuff muscles, allowing extensive movement but reduced stability.
Knee Injuries: Common from lateral blows, can damage ligaments and menisci, leading to functional impairment.
Ankle Injury Case Study: Examines common injuries and their implications.
Representative Joint Disorders:
Arthritis: Includes osteoarthritis and rheumatoid arthritis, leading to inflammation and joint damage.
Bursitis: Inflammation of bursa from repetitive use.
Tendinitis: Inflammation of tendons from overuse.