What condition is characterized by pain or stiffness in skeletal joints?

Arthritis is the condition characterized by pain or stiffness in skeletal joints. It refers to over 100 different types of inflammation or degeneration of the joints, where the main symptoms include swelling, pain, and reduced range of motion. This can significantly affect a person's quality of life and mobility. In cases of arthritis, the inflammation can be due to immune system responses, wear and tear on the joints, or infections, leading to discomfort and impaired joint function.

The other conditions mentioned do not primarily focus on joint pain or stiffness in the same way. Cancer may cause pain by affecting bones or joints but is not specifically associated with joint stiffness. Osteoporosis involves the weakening of bones, increasing the risk of fractures but not typically presenting with joint pain or stiffness. Fibromyalgia is a disorder characterized by widespread musculoskeletal pain and fatigue but does not specifically target skeletal joints in the way arthritis does. Therefore, arthritis is the most accurate answer to this question regarding skeletal joint concerns.