Final answer:
Scoliosis is the condition that causes a lateral curvature of the spine, often seen in adolescent girls, and may worsen during growth spurts. Treatment can range from observation to the use of a back brace or surgery, depending on severity.
Step-by-step explanation:
The condition that fourteen-year-old Mary is experiencing with a lateral curvature of the spine is called scoliosis. Scoliosis is an abnormal curvature of the spine that is often accompanied by twisting of the vertebral column. Compensatory curves may develop to help maintain balance, but the primary issue is the lateral curvature.
This condition is most prevalent among girls, and while the exact cause is often unknown, potential factors include muscle weakness, growth rate discrepancies between sides of the vertebral column, or limb length discrepancies. During adolescent growth spurts, scoliosis can worsen, and although many do not require treatment, some may need a back brace or even surgery in extreme cases.