Which condition is characterized by weak bones that break easily?

Osteoporosis is the condition characterized by weak bones that break easily. This is a common condition, particularly among older adults, where bone density decreases, leading to a higher risk of fractures. The typical process involves the loss of bone mass, which can occur due to various factors such as aging, hormonal changes (particularly menopause in women), and insufficient intake of calcium and vitamin D. In osteoporosis, the internal structure of the bone deteriorates and becomes more porous, resulting in bones that can readily fracture under stress that would normally not cause a break.

In contrast, osteoarthritis is primarily a degenerative joint disease that affects the cartilage and leads to pain and stiffness in joints. Osteomyelitis refers to an infection in the bone, which can result in bone damage but is not characterized solely by weak bones. A subdural hematoma is a collection of blood outside of blood vessels in the brain, typically due to head injuries, and is unrelated to bone density or strength. The specific focus of osteoporosis on the bone's strength and integrity distinguishes it clearly from the other conditions listed.