Presentation on theme: "Skeletal Joints I. Skeletal Joints- also called articulations (place where two or more bones meet) A. Functions of Joints: 1. Give skeleton mobility (allow."— Presentation transcript:
Skeletal Joints I. Skeletal Joints- also called articulations (place where two or more bones meet) A. Functions of Joints: 1. Give skeleton mobility (allow you to move!) 2. Hold skeleton together (protective function)
Skeletal Joints B. Classifying Joints 1. Structural classification focuses on materials used to bind bones together and/or the presence of a joint cavity. There are three classifications. a. Fibrous- the bones are united by fibrous tissues. The best examples are sutures of the skull. No movement allowed, no joint cavity
Skeletal Joints b. Cartilagenous- bone ends are connected by cartilage that acts as a shock absorber. Forms a strong joint. Examples include the pubic symphyses, intervertebral discs, hyaline cartilage, costal cartilage.
Skeletal Joints c. Synovial- articulating bones are separated by a joint cavity containing synovial fluid. These joints are moveable, and have four distinguishing features. 1) Articular cartilage- covers the ends of the bones forming the joint 2) Fibrous Articular Capsule- the sleeve or capsule of fibrous connective tissue 3) Joint Cavity- Cavity enclosed by the capsule that contains the synovial fluid 4) Reinforcing Ligaments- the capsule is supported with ligaments (connect bone to bone)
Skeletal Joints 2. Functional Classification (how much movement is allowed at a joint?) a. Synarthroses: immovable joints, Ex. Cranial Sutures b. Amphiarthroses: slightly moveable. Ex. Pubic Symphysis c. Diarthroses: freely moveable. Ex. Ball and Socket
Skeletal Joints C. Types of Synovial Joints 1. Plane Joint-allows nonaxial gliding movements, articular surfaces are flat. Ex. intercarpal joints 2. Hinge Joint- uniaxial movements, the cylindrical end of one bone fits into a trough- shaped surface of another bone. Ex. Elbow joint, phalanges, knee 3. Pivot Joint- uniaxial movements, the rounded end of one bone fits into a sleeve or ring of another, this allows rotation of one bone. Ex. Atlas and dens of axis, proximal radioulnar joint
Skeletal Joints 4. Condyloid Joint- biaxial movements, both articulating surfaces are oval and allow all angular motions. Ex. Radio carpal (wrist joint), occipital bone with atlas 5. Saddle Joint- biaxial movements, each articular surface has both concave and convex areas that fit together. Ex. Carpo-metacarpal joint of the thumb. Ex. Carpo-metacarpal joint of the thumb. 6. Ball and Socket Joint- multiaxial movements, spherical head of one bone articulates with the cuplike socket of another, most freely moving joint. Ex. Hip and shoulder joints Classification of Joints Classification of Joints
Skeletal Joints II. Joint Problems A. Causes 1. Inflammation of synovial cavity 2. Degeneration of the joint or articular cartilage B. Most common trauma-induced joint injuries 1. Sprain: the ligaments reinforcing a joint are stretched or torn. 2. Dislocation: bones are forced out of normal positions at the joint.
Skeletal Joints 3. Bursitis: inflammation of bursa through excessive friction, or direct injury 4. Tendonitis: inflammation of the tendon sheath, usually an overuse injury 5. Arthritis: cumulative effects of compression abrasions at joint surfaces When a joint is overused or injured suddenly, or when it remains under pressure for a long time, a nearby bursa can become inflamed. The sac fills with excess fluid, causing pressure on surrounding tissue. The immediate signal is pain, often accompanied by inflammation, swelling, and tenderness in the area. This is different from tendinitis, which is inflammation or irritation in the cord attaching muscle to bone, called a tendon.
Skeletal Joints a. Osteoarthritis: most common form, “wear and tear arthritis” that commonly affects older people. The articular cartilage softens, frays and begins to break down. b. Rheumatoid Arthritis: A Chronic inflammatory disorder. An autoimmune disorder (the body’s immune system attempts to destroy its own tissues). The disorder begins with an inflammation of synovial membranes that thicken and accumulate fluid. The scar tissue can eventually ossify and bones look deformed. c. Gouty Arthritis or Gout: a disease which uric acid accumulates in the blood and may be deposited as needle-shaped crystals in the soft tissues or joints.Gout tends to run in families.