X-ray of bunion

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Author: Mikael Häggström [notes 1]
Bunion (hallux valgus) is where the big toe often bends towards the other toes.


X-ray showing measurements of HV and IM angles of hallux valgus.

Bunion can be diagnosed and analyzed by projectional radiography ("X-ray"), which should be weight-bearing.[1] The hallux valgus angle (HVA) is the angle between the longitudinal axes of the proximal phalanx and the first metatarsal bone of the big toe. It is considered abnormal if greater than 15–18°.[2] The following HV angles can also be used to grade the severity of hallux valgus:[3]

  • Mild: 15–20°
  • Moderate: 21–39°
  • Severe: ≥ 40°

The intermetatarsal angle (IMA) is the angle between the longitudinal axes of the first and second metatarsal bones, and is normally less than 9°.[2] The IM angle can also grade the severity of hallux valgus as:[3]

  • Mild: 9–11°
  • Moderate: 12–17°
  • Severe: ≥ 18°


Presence or absence of hallux valgus, and the numerical values of the HV and IM angles.

See also: General notes on reporting


  1. For a full list of contributors, see article history. Creators of images are attributed at the image description pages, seen by clicking on the images. See Radlines:Authorship for details.


  1. Page 533 in: Sam W. Wiesel, John N. Delahay (2007). Essentials of Orthopedic Surgery (3 ed.). Springer Science & Business Media. ISBN 9780387383286. 
  2. 2.0 2.1 Rebecca Cerrato, Nicholas Cheney. Hallux Valgus. American Orthopaedic Foot & Ankle Society. Retrieved on 2016-12-30. Last reviewed June 2015
  3. 3.0 3.1 Piqué-Vidal, Carlos; Vila, Joan (2009). "A geometric analysis of hallux valgus: correlation with clinical assessment of severity ". Journal of Foot and Ankle Research 2 (1). doi:10.1186/1757-1146-2-15. ISSN 1757-1146.