Which condition is characterized by an abnormal lateral curvature of the spine?

Scoliosis is specifically defined as an abnormal lateral curvature of the spine, which can manifest in various degrees of severity. This condition often develops during the growth spurts just before puberty and can result from various causes, including genetic factors, congenital issues, or neuromuscular conditions. The curvature can lead to discomfort, postural changes, and potential complications with lung and heart function if it becomes severe.

In contrast, kyphosis refers to an excessive outward curvature of the spine, usually in the thoracic area, leading to a hunched back appearance. Lordosis involves an exaggerated inward curvature of the lower back, often described as swayback. Osteoporosis, on the other hand, is a condition characterized by weak and brittle bones but does not directly relate to spinal curvature. Thus, the defining characteristic of scoliosis as an abnormal lateral deviation makes it the correct answer in this context.