Q.An excessive inward (forward) curvature of the lumbar region of the spine, with the abdomen protruding forward, is called:

A spinal deformity marked by an exaggerated inward (concave) curve in the lumbar region together with a protruding abdomen points to one specific postural deviation.

Lordosis is the excessive anterior (forward) curvature of the lumbar spine. The natural lumbar curve becomes exaggerated, tilting the pelvis forward and pushing the abdomen outward while the buttocks protrude backward. This "swayback" posture is exactly what the question describes.

Why the others are wrong:

• (a) Kyphosis is an excessive outward (posterior) curvature of the thoracic spine, creating a rounded upper back or "hunchback" appearance — the opposite direction of curve. …

The spine has natural curves that distribute mechanical stress and maintain balance. In the lumbar region—the lower back—a gentle inward (concave) curve is normal. When that curve becomes excessive, the pelvis tilts forward, the abdomen juts out, and the buttocks appear prominent. This postural deformity is lordosis, sometimes called swayback.

Understanding why the spine curves this way helps distinguish lordosis from other deformities. The lumbar vertebrae sit above the pelvis; if the hip flexors are tight or the abdominal muscles weak, the pelvis rotates anteriorly, pulling the lumbar spine into hyperextension. The result is that characteristic hollow in the lower back and the belly pushed forward.

Now consider each option:

1. Kyphosis is an excessive outward (convex) curve of the thoracic spine—the upper and mid-back. It produces a rounded, hunched appearance, the opposite direction of curvature from what the question describes. Wrong.
2. Scoliosis is a lateral (sideways) curvature of the spine, visible when viewing the back from behind. It has nothing to do with forward or backward curves in the sagittal plane. Wrong.
3. Lordosis matches exactly: an exaggerated inward lumbar curve with anterior pelvic tilt and abdominal protrusion. Correct. …