joints

Chapter 8: Joints of the Skeletal System

Articulations: Functional junctions between bones.
- Bind parts of the skeletal system together.
- Support bone growth and flexibility during childbirth.
- Enable movement in response to skeletal muscle contraction.

Fibrous Joints: Dense connective tissues connect bones that are in close contact.
Cartilaginous Joints: Bones connected by hyaline cartilage or fibrocartilage.
Synovial Joints: Most complex; allow free movement.
- Synarthrotic: Immovable joints.
- Amphiarthrotic: Slightly movable joints.
- Diarthrotic: Freely movable joints.

Types of Fibrous Joints:
- Syndesmosis: A sheet or bundle of fibrous tissue connects bones (e.g., between tibia and fibula).
- Suture: Joint between flat bones with a thin layer of connective tissue, allowing no movement.
- Gomphosis: Cone-shaped bony process fits into a socket (e.g., tooth in jawbone).

Types of Cartilaginous Joints:
- Synchondrosis: Bands of hyaline cartilage unite bones (e.g., epiphyseal plate).
- Symphysis: A fibrocartilage pad between bones (e.g., pubic symphysis).

Characterized by a joint cavity, synovial fluid, articular cartilage, and a joint capsule.

Ball-and-Socket Joint: Hip and shoulder joints allow multi-directional movement.
Condyloid Joint: Found between metacarpals and phalanges, allowing movement but not rotation.
Gliding Joint: Present between carpals and tarsals.
Hinge Joint: Examples include elbow and phalanges.
Pivot Joint: Found between the proximal ends of the radius and ulna.
Saddle Joint: Found between the carpal and metacarpal of the thumb.

Flexion/Extension/Hyperextension: Movements that change the angle between two body parts.
Abduction/Adduction: Movements away from or towards the body's midline.
Dorsiflexion/Plantarflexion: Movements involving the foot.
Rotation/Circumduction: Rotational and circular movements.
Eversion/Inversion: Movements of the foot.
Protraction/Retracting: Movement forward and backward.
Elevation/Depression: Movements up and down.

Shoulder Joint: A ball-and-socket joint providing a wide range of movement, reinforced by ligaments and bursae.
Elbow Joint: A hinge joint characterized by stability and movement primarily in flexion and extension.
Hip Joint: Heavier than the shoulder joint, it also functions as a ball-and-socket joint but with less freedom of movement.
Knee Joint: The largest and most complex joint, functioning mainly in flexion and extension, supported by ligaments and tendons.

Joint stiffness often marks the onset of aging.
- Fibrous joints are most susceptible to change.
- Decreased flexibility in symphyses diminishes height.
- Synovial joints lose elasticity and blood supply with age.
- Regular activity can help maintain joint function.

Sprains: Injury to ligaments or tendons due to twisting motion.
Bursitis: Inflammation of a bursa often due to overuse.
Arthritis: Inflammation and swelling of joints, with types including rheumatoid arthritis, osteoarthritis, and gout.