Final answer:
The specific term for a reduction in the normal curvature of the spine is not commonly used, but spine curvature disorders include kyphosis (excessive posterior curvature), lordosis (excessive anterior curvature), and scoliosis (abnormal lateral curvature).
Step-by-step explanation:
The term that refers to a reduction in the normal curvature of the spine is not specified in common medical terminology as disorders typically refer to an excessive curvature. However, the terms related to spine curvature disorders include kyphosis, an excessive posterior curvature of the thoracic region; lordosis, an excessive anterior curvature of the lumbar region; and scoliosis, an abnormal lateral curvature accompanied by twisting of the vertebral column. While these terms describe an increase rather than a reduction, they are relevant to understanding spinal curvature disorders.
Kyphosis, also known as humpback or hunchback, can result from conditions like osteoporosis, which weakens and erodes the anterior portions of the upper thoracic vertebrae, causing their gradual collapse. Lordosis, or swayback, often occurs with factors such as obesity or late pregnancy that cause an anterior pelvic tilt and a pronounced lumbar curve. Scoliosis represents an abnormal lateral and twisting curvature of the spine, which can worsen during adolescent growth spurts and may require treatment such as a back brace or surgery in severe cases.