What term describes a decreased anterior lumbar curve and an increased posterior thoracic curve from neutral?

The term that accurately describes a decreased anterior lumbar curve and an increased posterior thoracic curve from neutral is "sway-back." This postural condition is characterized by a particular alignment where the pelvis tilts posteriorly, leading to a flattening of the lumbar region and often an increase in the curvature of the thoracic spine. This posture results in a shift of the center of gravity and can have implications for movement and stability.

Sway-back posture typically presents with the pelvis positioned more behind the feet, which contributes to the described curvature changes. In persons with sway-back, the lumbar spine loses its natural lordotic curve (the inward curve), and the thoracic spine, where the ribcage is found, may appear more rounded. This creates a distinctive postural profile compared to other conditions that focus on either excessive curvature in one area or flatness throughout.

Other terms like lordosis and kyphosis pertain specifically to an increased curve in the lumbar or thoracic regions, respectively, but do not encompass the combination of decreased lumbar and increased thoracic curvature. Flat back posture refers to a loss of the normal curves, typically resulting in a straightened appearance of the spine, rather than the specific changes described in the question. Thus, the best