Scoliosis is most commonly diagnosed between ages 10 and 18, during the rapid growth spurts of adolescence. This form, called adolescent idiopathic scoliosis, accounts for the vast majority of cases and affects roughly 1% to 3% of adolescents in the United States. But scoliosis can also be detected much earlier in childhood or appear for the first time in older adulthood, depending on its cause.
Adolescent Idiopathic Scoliosis: Ages 10 to 18
The most common type of scoliosis has no known underlying cause, which is what “idiopathic” means. It develops during the adolescent growth spurt and is defined as a sideways spinal curve of 10 degrees or more. Up to 4 in 100 adolescents have some degree of this curvature, though most cases are mild and never require treatment.
This is the age window when scoliosis is most likely to be caught because the spine is growing quickly, and curves that were previously unnoticeable can progress in a short period. A curve that measures 10 degrees at age 11 might stay stable or might worsen significantly over the next few years, which is why monitoring during this period matters.
When Screening Typically Happens
Several major medical organizations, including the American Academy of Pediatrics and the American Academy of Orthopaedic Surgeons, recommend screening girls at ages 10 and 12 and boys once at age 13 or 14. The one-to-two-year gap between boys and girls reflects the difference in when puberty and growth spurts typically begin.
Screening usually involves the Adam’s Forward Bend Test, where a child bends forward at the waist while a provider checks for asymmetry in the ribs or back. A small handheld device called a scoliometer can measure the angle of trunk rotation during this test. If the reading falls between 5 and 7 degrees or higher, an X-ray is typically the next step to measure the actual curve and confirm a diagnosis.
It’s worth noting that the U.S. Preventive Services Task Force has not endorsed routine screening, concluding that the evidence is insufficient to weigh the benefits against the harms for children aged 10 to 18. Some schools still include scoliosis checks, but this varies widely by state. If your child’s school doesn’t screen, a pediatrician can do the same check during a well-child visit.
Earlier Diagnosis: Birth Through Age 9
Scoliosis diagnosed before age 10 falls into two categories. Infantile scoliosis covers birth through age 2, and juvenile scoliosis covers ages 3 through 9. Both are far less common than the adolescent form, but they can be more concerning because a young child has many more years of growth ahead, giving a curve more time to worsen.
Congenital scoliosis is a separate category entirely. It results from vertebrae that don’t form correctly during fetal development, so the condition is present at birth even if it isn’t immediately obvious. Parents sometimes notice it first through small clues: buttons on a shirt that don’t line up evenly, a shirt that seems to twist around the torso, or one pant leg that hangs longer than the other. Congenital scoliosis can progressively worsen as a child grows, so early detection often leads to closer monitoring or earlier intervention.
Scoliosis Diagnosed in Adulthood
Not all scoliosis starts in childhood. Degenerative scoliosis develops in grown adults, usually after age 50, as the discs and joints of the spine wear down over time. It’s driven by osteoarthritis of the spine and sometimes by osteoporosis, both of which become more common with age. Like other forms, it’s defined as a curve of 10 degrees or more.
Some adults diagnosed with scoliosis actually had a mild curve during adolescence that was never detected or never caused problems. As the spine ages and loses structural support, that existing curve can progress. Others develop a completely new curve in a part of the spine that was previously straight. Either way, the symptoms that bring adults to a doctor tend to be different from those in teenagers. Pain, stiffness, and difficulty standing upright are more common complaints than the visible asymmetry that prompts diagnosis in younger patients.
What Determines When a Curve Gets Caught
The age at diagnosis depends heavily on how fast the curve progresses and whether anyone is looking for it. A 25-degree curve is usually visible to a trained eye, but a 12-degree curve in a teenager wearing loose clothing can go unnoticed for years. Children who skip well-child visits or attend schools without screening programs are more likely to be diagnosed later, sometimes after the curve has already become significant.
Growth velocity is the biggest risk factor for progression. Girls who are diagnosed before they’ve had their first period are at higher risk of their curve worsening because they still have substantial growing left to do. Boys tend to be diagnosed a year or two later than girls, partly because their growth spurts start later and partly because screening guidelines reflect that timing. A curve discovered early in puberty, when the spine is growing fastest, requires more frequent monitoring than one found near the end of growth.
For parents wondering whether their child’s posture looks off, the signs to watch for include one shoulder sitting higher than the other, a waistline that appears uneven, or a rib cage that seems more prominent on one side when the child bends forward. These don’t always mean scoliosis, but they’re worth bringing up at the next checkup.