Joints - BIOL 2457 Anatomy & Physiology I - PDF

Joints BIOL 2457 Anatomy & Physiology I 1  Learning Objectives By the end of this lesson, students will be able to: 1. Explain what a joint is. 2. List the major structural classifications and functional classifications of joints. 3. Describe the...

Joints BIOL 2457 Anatomy & Physiology I 1  Learning Objectives By the end of this lesson, students will be able to: 1. Explain what a joint is. 2. List the major structural classifications and functional classifications of joints. 3. Describe the general structure of fibrous joints. 4. List examples of each specific kind of fibrous joint. 5. Describe the general structure of cartilaginous joints. 6. List examples of each specific kind of cartilaginous joint. 7. Describe the general structure of synovial joints, including a description of their major structures. 8. Describe the functions of bursae & tendon sheaths in synovial joints. 9. List specific examples of each of the six types of synovial joints. 10.List the movements of each of the six types of synovial joints. 11.Describe the relationship between joint stability & joint mobility. 12.Explain the anatomical basis for sprains, dislocations, cartilage tears, bursitis, and tendonitis. 13.Identify similarities and differences between the three types of arthritis. 2  Introduction to Joints Joints (articulations) are locations where bones meet Functions of joints Connecting bones together Allowing body movement Joints can be classified 2 ways How the bones interact (structural) How much they move (functional) 3  Joint Classifications STRUCTURAL - held together FUNCTION AL movement 4 Functional Classifications of Joints Synarthroses are immovable joints Amphiarthroses are slightly moveable joints Diarthroses are freely moveable joints 5  Structural Classification of Joints Fibrous joints are bones connected with collagen fibers. These joints are amphiarthroses or synarthroses. Type #1: Sutures Type #2: Gomphoses Type #3: Syndesmoses Location: between skull bones Location: between roots & Location: between radius & sockets ulna AND tibia & fibula Movement level: synarthrosis Movement level: synarthrosis Movement level: amphiarthrosis The periodontal ligament is the name of the collagen fibers in this joint. 6  Structural Classification of Joints Cartilaginous joints are made of bones connected with cartilage These joints are function as amphiarthroses or synarthroses Type #1: Synchondroses Type #2: Symphyses Locations: the epiphyseal plate, attaching rib #1 Location: between the vertebra to the sternum. (intervertebral discs) AND between halves of the Can become synostoses (if calcified) hip (pubic symphysis) Movement level: synarthrosis Movement level: amphiarthrosis 7  Structural Classification of Joints Synovial joints are diarthrotic joints with an articular capsule General structure of synovial joints: Articular cartilage, hyaline covering the boney surfaces The joint cavity, a space filled with synovial fluid Synovial fluid, which reduces friction & feeds chondrocytes ** The articular capsule fibrous capsule holds bones together synovial membrane produces synovial fluid internal capsule has no nerves (pain perception is **Synovial external) fluid functions: shock absorption Reinforcing ligaments, which strengthen the joint overall lubrication nutrients for 8  Synovial Joint Support Structures Synovial joints use bursae & tendon sheaths to reduce friction or pressure Bursae are fluid-filled connective tissue sacs Tendon sheaths (a type of bursae) surround tendons These are found where soft tissues rub each other or rub hard tissues They do not provide structural support like other accessory structures: bones, ligaments, tendons, muscle, and even fat pads. 9  Synovial Joint Movements The structure of a synovial joint determines how many directions it can move in Plane joints are non- axial (only gliding Condylar joints & movements) saddle joints are biaxial (movement along 2 axes) Ball-and-socket joints are multi-axial (movement along 3 Hinge joints & pivot axes) joints are uniaxial (movement along 1 axis) 10  Types of Synovial Joints Plane joint Classification: non-axial Examples: intercarpal joints, intervertebral joints Hinge joint Classification: uniaxial Examples: elbow, knee, ankle, & interphalangeal joints 11  Types of Synovial Joints Pivot joint Classification: uniaxial Examples: proximal radioulnar joint, atlantoaxial joint (between the atlas & axis) Condylar joint Classification: biaxial Examples: metacarpophalangeal joints, radiocarpal joints 12  Types of Synovial Joints Saddle joint Classification: biaxial Examples: carpometacarpal joint of the thumb Ball-and-socket joint Classification: multiaxial Examples: shoulder and hip 13  Synovial Joint Movements Synovial joints move in three general ways: Gliding movements  two bones slide past each other This occurs where 2 flat boney surfaces meet. Angular movements  the angle between two bones increases or decreases Rotational movements  a bone rotates around its axis ABDUCTI ADDUCTI LATERAL/MEDIAL FLEXION EXTENSION ON ON ROTATION Special movements cannot be classifed as any of these others 14  Angular Synovial Joint Movements Movements Flexion: the angle between bones decreases (they move closer together) Extension: the angle between bones increases (they move farther apart) Hyperextension: a bone extends beyond the anatomical position *The knee joint is “backwards” compared to other body joints!* 15  Angular Synovial Joint Movements Movements Abduction: moving a structure away from the midline of the body Adduction: moving a structure toward the midline of the body Circumduction: moving a limb in a “cone” (distal aspect in a circle, proximal aspect unmoved) 16  Rotational Synovial Joint Movements Movements Medial Rotation: the bone turns toward Lateral Rotation: the bone the midline of the body turns away from the midline of the body 17  Special Synovial Joint Movements Movements Pronation: rotating the hand Plantarflexion: the toes medially press downward Supination: rotating the hand Dorsiflexion: the toes pull laterally upward ◦ also called plantar extension Inversion: the foot rolls medially Eversion: the foot rolls laterally 18  Synovial Joint Movements Special Movements Protraction: a structure Elevation: a structure moves forward moves up Retraction: a structure Depression: a structure moves backward moves down Opposition: the thumb comes together with another finger 19  Synovial Joint Disorders – Cartilage Tears Cartilage helps to stabilize joints & absorb shock Cartilage naturally breaks down with age In younger people, cartilage damage is typically due to accidents or sports injuries Damage to synovial joint cartilage initially leads to swelling at the joint Cartilage tears are most common in the Ultimately, the joint may stop bending / knee (in the cartilage called the meniscus) straightening The more mobile the joint, the less stable 20 The more stable the joint,  Synovial Joint Disorders – Bursitis & Tendonitis Tendonitis occurs when a tendon (or its tendon sheath) become inflamed & swollen. This is typically caused by injury or overuse. Bursitis occurs when the bursa near the synovial joints become inflamed & swollen. This is typically caused by friction or injury. 21  Synovial Joint Disorders – Sprains & Dislocations Dislocations occur when bones are forced out of their Sprains occur normal alignment when ligaments are stretched Sprains, inflammation, and immobility usually occur because of dislocations or torn Once repositioned, the joint will heal 22  Synovial Joint Disorders – Arthritis Osteoarthritis is the most common kind of arthritis By age 80, most people have some osteoarthritis symptoms In osteoarthritis, the articular cartilage softens & degenerates Joints make a crunching sound called crepitus Bone spurs develop on the exposed bone tissue Osteoarthritis is caused by years of joint wear & tear It develops slowly and irreversibly. 23 Synovial Joint Disorders – Arthritis Rheumatoid arthritis is the autoimmune form of arthritis White blood cells release inflammatory chemicals into the synovial joint cavities The cartilage gets broken down Pannus (scar tissue) replaces it Pannus ossifies, leading to deformed joints Rheumatoid arthritis is treated with immunosuppressants, anti- inflammatory medications, and pain medications 24  Synovial Joint Disorders – Arthritis Gouty arthritis is caused by uric acid crystals in the joints Normally, uric acid is excreted in the urine If levels are too high, it forms “needles” inside the joints The immune system attacks the crystals in the joint This leads to pain This immobilizes the joint This damages the joint Gouty arthritis is treated with anti-inflammatory medications, pain medications and increased water consumption 25 26