Cobb angle

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Measurement of scoliosis

title: "Cobb angle" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["musculoskeletal-radiographic-signs"] description: "Measurement of scoliosis" topic_path: "general/musculoskeletal-radiographic-signs" source: "https://en.wikipedia.org/wiki/Cobb_angle" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Measurement of scoliosis ::

::figure[src="https://upload.wikimedia.org/wikipedia/commons/8/81/Scoliosis_cobb.svg" caption="89° Cobb angle measurement of a levoscoliosis"] ::

The Cobb angle is a measurement of bending disorders of the vertebral column such as scoliosis and traumatic deformities.

Definition and method

It is defined as the greatest angle at a particular region of the vertebral column, when measured from the superior endplate of a superior vertebra to the inferior endplate of an inferior vertebra. However, the endplates are generally parallel for each vertebra, so not all sources include usage of a superior versus inferior endplate in the definition.

Unless otherwise specified it is generally presumed to refer to angles in the coronal plane, such as projectional radiography in posteroanterior view. In contrast, a sagittal Cobb angle is one measured in the sagittal plane such as on lateral radiographs.{{cite journal|last1=Schmitz|first1=A. |last2=Jaeger|first2=U. |last3=Koenig|first3=R. |last4=Kandyba|first4=J. |last5=Gieske|first5=J. |last6=Schmitt|first6=O. |title=Sagittale Cobb-Winkel-Messungen bei Skoliose mittels MR-Ganzwirbelsäulenaufnahme|journal=Zeitschrift für Orthopädie und ihre Grenzgebiete|volume=139|issue=4|year=2001|pages=304–07|issn=0044-3220|doi=10.1055/s-2001-16915|pmid=11558047 |s2cid=260354772 }}

Cobb angles are preferably measured while standing, since lying down decreases Cobb angles by around 7–10°.

Uses

It is a common measurement of scoliosis.

The Cobb angle is also the preferred method of measuring post-traumatic kyphosis in a recent meta-analysis of traumatic spine fracture classifications.

Severity

::data[format=table]

SeverityCobb angle
Not scoliosistitle=The Complete Scoliosis Surgery Handbook for Patients: An In-Depth and Unbiased Look Into What to Expect Before and During Scoliosis Surgery
Mild scoliosis10–30°
Moderate scoliosistitle=ERS Handbook: Self-Assessment in Respiratory Medicine
Severe scoliosis45°
::

Those with Cobb angle of more than 60° usually have respiratory complications.

Scoliosis cases with Cobb angles between 40 and 50 degrees at skeletal maturity progress at an average of 10 to 15 degrees during a normal lifetime. Cobb angles of more than 50 degrees at skeletal maturity progress at about 1 to 2 degrees per year.

History

The Cobb angle is named after the American orthopedic surgeon John Robert Cobb (1903–1967). It was originally used to measure coronal plane deformity on radiographs with antero-posterior projection for the classification of scoliosis. It has subsequently been adapted to classify sagittal plane deformity, especially in the setting of traumatic thoracolumbar spine fractures.

References

References

  1. Brian D. Coley. (2013). "Caffey's Pediatric Diagnostic Imaging". Elsevier Health Sciences.
  2. Fred F. Ferri. (2017). "Ferri's Clinical Advisor 2018 E-Book". Elsevier Health Sciences.
  3. (2014). "Supine to standing Cobb angle change in idiopathic scoliosis: the effect of endplate pre-selection". Scoliosis.
  4. Keynan, Ory. (Mar 1, 2006). "Radiographic measurement parameters in thoracolumbar fractures: a systematic review and consensus statement of the spine trauma study group.". Spine.
  5. Dr. Kevin Lau. "The Complete Scoliosis Surgery Handbook for Patients: An In-Depth and Unbiased Look Into What to Expect Before and During Scoliosis Surgery". Health In Your Hands.
  6. Konrad E. Bloch, Thomas Brack, Anita K. Simonds. (2015). "ERS Handbook: Self-Assessment in Respiratory Medicine". European Respiratory Society.
  7. (2002). "Adolescent idiopathic scoliosis: radiologic decision-making". Am Fam Physician.
  8. Cobb JR. Outline for the study of scoliosis. The American Academy of Orthopedic Surgeons Instructional Course Lectures. Vol. 5. Ann Arbor, MI: Edwards; 1948.

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::

musculoskeletal-radiographic-signs