Final answer:
Kyphosis is the age-related change indicated by Mrs. Jones' curvature of the spine, commonly referred to as dowager's hump. It is caused by fractures of the thoracic vertebrae due to a significant decrease in bone mass, which is associated with osteoporosis.
Step-by-step explanation:
**Kyphosis** is the age-related change indicated by Mrs. Jones' curvature of the spine, commonly referred to as dowager's hump. Kyphosis is defined as excessive curvature of the spinal column in the thoracic region, and it often occurs due to fractures of the thoracic vertebrae. These fractures can result from a significant decrease in bone mass, which is a characteristic of **osteoporosis**, an age-related disorder that causes the gradual loss of bone density and strength.
As people age, accumulated spinal column injuries and diseases like osteoporosis can lead to curvatures of the spine, resulting in a stooping posture frequently seen in the elderly.