Final answer:
Thoracic spine extension is limited by the rib cage and vertebral orientation with an estimated ROM of 20-25 degrees, while lumbar spine extension is substantial with a typical ROM of 15-20 degrees, influenced by the orientation of the articular processes.
Step-by-step explanation:
The normal Range of Motion (ROM) limits for the thoracic and lumbar spine in extension vary due to differences in vertebral anatomy and Articular Joint characteristics in these two regions. In the thoracic spine, the presence of the rib cage and the orientation of the vertebrae limit motion, specifically restricting flexion, extension, and lateral flexion. However, a greater degree of rotation is permitted due to the flattened and vertically positioned thoracic articular processes.
The lumbar region, on the other hand, offers considerable extension and flexion as well as lateral flexion, but is limited in rotation because of the orientation of the articular processes. While specific numerical values are not provided, general clinical observations suggest that thoracic extension is estimated to range from 20 to 25 degrees, while lumbar extension ranges from 15 to 20 degrees. These ROM limits can vary from individual to individual.
Understanding the different degrees of motion, specifically the extension capabilities of each spinal segment, is important for assessments and treatments in healthcare and fitness domains.