Joints
- Joints are points of contact between bones, or between bones and cartilages. 3 types:
- Fibrous (immovable) joints: E.g. sutures b/w skull bones.
- Cartilaginous joints (Slightly movable joints): Bones are joined together with the help of cartilages. E.g. Joints between the adjacent vertebrae.
- Synovial (movable) joints: They have a fluid filled synovial cavity between articulating surfaces of 2 bones.
Types of Synovial Joint
| Joint | Examples |
|---|---|
| Ball & socket | Shoulder joint & hip joints. |
| Hinge joint | Knee joint, elbow joint, phalanges joints |
| Pivot joint | Joints b/w atlas & axis. |
| Gliding joint | Joints b/w carpals |
| Saddle joint | Joints b/w carpal & metacarpal of thumb |
Disorders of Muscular & Skeletal Systems
- Myasthenia gravis: An auto immune disorder that affects neuromuscular junction. It leads to fatigue, weakening and paralysis of skeletal muscles.
- Muscular dystrophy: Progressive degeneration of skeletal muscles. Mostly due to genetic disorder.
- Tetany: Rapid muscle spasm due to low Ca2+ in body fluid.
- Arthritis: Inflammation of joints.
- Osteoporosis: Age-related disorder characterized by decreased bone mass and increased chances of fractures. Decreased level of estrogen is a common cause.
- Gout: Inflammation of joints due to accumulation of uric acid crystals.