The two main types of kyphosis are postural kyphosis and Scheuermann’s kyphosis. Postural kyphosis comes from habit and muscle imbalance, while Scheuermann’s kyphosis is a structural condition where the vertebrae themselves grow into a wedge shape. The distinction matters because one can be corrected with effort, and the other requires medical management. A normal upper back curves forward between roughly 20 and 45 degrees; beyond that range, the curve is considered excessive.
Postural Kyphosis
Postural kyphosis is by far the more common type. It develops when prolonged slouching, hunching over screens, or poor sitting habits stretch out the ligaments and muscles that hold the spine upright. Over time, the upper back rounds forward more than it should. The vertebrae themselves are still normal in shape. If you stand up straight or lie flat, the curve disappears or significantly reduces, which is the hallmark of postural kyphosis: it’s flexible.
The underlying problem is a muscle imbalance. The back extensor muscles and core abdominal muscles weaken from disuse, while the hamstrings and chest muscles tighten. This combination pulls the upper spine into a rounded position that gradually starts to feel “normal.” Symptoms tend to be mild, often limited to upper back stiffness, fatigue after sitting for long periods, and tight hamstrings.
Because the spine itself isn’t damaged, postural kyphosis responds well to physical therapy and targeted exercise. Strengthening the abdominal and back muscles while stretching the hamstrings and chest can progressively pull the spine back into alignment. Postural kyphosis doesn’t typically progress to the point of needing a brace or surgery, though it can become harder to reverse the longer it goes uncorrected.
Scheuermann’s Kyphosis
Scheuermann’s kyphosis is a structural problem, meaning the bones themselves are misshapen. During adolescence, the front edges of several vertebrae in a row grow more slowly than the back edges, causing them to become wedge-shaped. When stacked together, these wedged vertebrae create a rigid forward curve that doesn’t straighten out when you change position or try to stand tall.
The diagnostic criteria are specific: at least three adjacent vertebrae must each show 5 degrees or more of anterior wedging, and the overall curve must exceed 40 degrees. This combination confirms Scheuermann’s disease rather than a simple postural issue. The cause isn’t fully understood, but genetics play a role, and it typically appears during the growth spurt years, between ages 12 and 15.
Scheuermann’s kyphosis tends to cause more pain than postural kyphosis, particularly during the teenage years when the condition is actively developing. The rigid curve also makes the upper back noticeably rounded in a way that doesn’t change with posture correction. For children still growing whose curves exceed 65 degrees, bracing can help prevent further progression. Surgery is reserved for severe cases where the curve continues to worsen or causes significant pain that doesn’t respond to other treatment.
How to Tell Them Apart
The simplest test is flexibility. If you lie face-down on a flat surface and the rounded curve flattens out, it’s likely postural. If the curve stays rigid regardless of position, it points toward Scheuermann’s. A doctor can confirm the difference with a lateral X-ray of the spine, which reveals whether the vertebrae are wedge-shaped and measures the exact degree of curvature.
Age of onset also offers clues. Postural kyphosis can appear at any age and tends to develop gradually in people with sedentary lifestyles. Scheuermann’s kyphosis almost always becomes apparent during adolescence and doesn’t develop later in life, though its effects persist into adulthood if untreated.
Other Causes of Excessive Curvature
While postural and Scheuermann’s are the two primary types, kyphosis can also develop from other conditions. Congenital kyphosis occurs when the spinal column doesn’t form properly during fetal development, and it’s present from birth. This is rarer and typically identified early in childhood.
In older adults, osteoporosis is a major driver of kyphosis. When bones lose density, the vertebrae can collapse under normal body weight, creating wedge-shaped compression fractures. About 25% of women over 50 have at least one of these fractures, and by age 80, the number climbs to 40 to 50%. Each fractured vertebra adds a few degrees of forward curvature, and the resulting hunched posture, sometimes called a dowager’s hump, places extra stress on neighboring vertebrae, making additional fractures more likely. This creates a cascading effect where the curve progressively worsens over time.
Roughly 1 to 1.5 million vertebral compression fractures occur in the United States each year, making osteoporotic kyphosis a significant health concern for aging populations. Unlike Scheuermann’s, this type of structural kyphosis develops later in life and is directly linked to bone health rather than abnormal growth patterns.