Select the correct statement about disorder of muscular or skeletal system

Options

A. Muscular dystrophy-Autoimmune disortening of muscles
B. Myasthenia gravis -Autoimmune disorder which inhibits sliding of myosin filaments
C. Gout - Inflammation if joints due to extra deposition of calcium
D. Osteoporosis - Decrease in bone mass and higher chances of fractures with advancing age.

Answer

To solve the question regarding the correct statement about disorders of the muscular or skeletal system, we can analyze each option provided in the question.

### Step-by-Step Solution:

1. **Analyze the first statement: Muscular dystrophy is an autoimmune disorder causing distortion of the muscles.**
- Muscular dystrophy is characterized by progressive weakening and degeneration of skeletal muscles. It is primarily a genetic disorder, not an autoimmune one. Therefore, this statement is **false**.

2. **Analyze the second statement: Myasthenia gravis is an autoimmune disorder that inhibits the sliding of the myosin filaments.**
- Myasthenia gravis is indeed an autoimmune disorder, but it affects the neuromuscular junction rather than directly inhibiting the sliding of myosin filaments. It leads to muscle fatigue and weakness, especially after prolonged activity. Thus, this statement is also **false**.

3. **Analyze the third statement: Gout is inflammation of the joints due to extra deposition of calcium.**
- Gout is characterized by inflammation of the joints due to the accumulation of uric acid crystals, not calcium. Therefore, this statement is **false**.

4. **Analyze the fourth statement: Osteoporosis is a decrease in bone mass with higher chances of fractures with advancing age.**
- Osteoporosis is indeed a condition that involves a decrease in bone mass, leading to an increased risk of fractures, particularly in older adults. This is true and is often associated with a decrease in estrogen levels as individuals age. Hence, this statement is **true**.

### Conclusion:
The correct statement about disorders of the muscular or skeletal system is the fourth one regarding osteoporosis.