What degree of spinal curvature is considered sufficient to diagnose scoliosis in both children and adults?

Diagnostic Threshold for Scoliosis

A lateral spinal curvature of more than 10 degrees on a standing posteroanterior radiograph is the conventional definition of scoliosis, applicable to both children and adults. 1

Standard Diagnostic Criteria

• Scoliosis is defined as a Cobb angle exceeding 10 degrees measured on standing PA radiographs, representing an abnormal 3-D curvature of the spine 1, 2, 3
• This 10-degree threshold applies universally across all age groups—pediatric, adolescent, and adult populations 1, 2, 4
• The measurement must be performed on weight-bearing (standing) radiographs to accurately assess the deformity under physiologic loading conditions 1

Clinical Context and Progression Risk

While 10 degrees establishes the diagnostic threshold, clinical significance varies by skeletal maturity:

• Skeletally immature patients with curves under 20 degrees have less than 30% risk of progression and typically require only observation 5
• Curves exceeding 20 degrees in skeletally immature patients have progression likelihood exceeding 70%, warranting referral to orthopedic specialists 6, 5
• Curves between 20-26 degrees may be considered for bracing, while curves between 26-45 degrees should undergo bracing and specialist management 6

Measurement Technique

• The Cobb angle is measured by identifying the most tilted vertebrae at the upper and lower ends of the curve, drawing lines along their endplates, and measuring the angle between perpendiculars to these lines 1
• Measurement error of ±5 degrees is considered clinically acceptable, representing the inherent variability of the Cobb method 7, 8
• Radiography remains the primary imaging modality for diagnosing, classifying, and monitoring scoliosis progression 1

Important Caveats

• The diagnosis of idiopathic scoliosis is one of exclusion—underlying neuromuscular disorders, congenital vertebral anomalies, infections, and skeletal dysplasias must be ruled out 1
• Curves measuring 10-20 degrees represent mild scoliosis that is usually asymptomatic and does not cause disability or functional impairment 3
• Any curve in a child under 10 years of age, regardless of magnitude, warrants specialist referral due to higher risk of progression and potential underlying pathology 4