Which disease is NOT considered a disease of the musculoskeletal system?

Asthma is classified as a respiratory disease and does not affect the musculoskeletal system, which includes bones, muscles, cartilage, tendons, and ligaments. Conditions like arthritis, osteoporosis, and muscular dystrophy, on the other hand, are directly related to the muscles, joints, and skeletal structure.

Arthritis involves inflammation of the joints, leading to pain and stiffness. Osteoporosis is characterized by decreased bone density, making bones fragile and more prone to fractures. Muscular dystrophy is a genetic disorder that causes progressive weakness and loss of muscle mass. Since asthma involves the airways and breathing, it clearly stands apart from these musculoskeletal disorders, highlighting why it is the correct answer to the question.