Intermetatarsal angle

Last revised by Leonardo Lustosa on 16 Jan 2023

The intermetatarsal angle is a measurement used to assess hallux valgus and metatarsus primus varus deformities.

The term intermetatarsal angle alone typically refers to assessment of the first and second metatarsals. Occasionally the term first intermetatarsal angle is used to specify that this angle is referred to instead of the fourth-fifth intermetatarsal angle.

The intermetatarsal angle is measured on AP foot radiographs between the long axes of the 1st and 2nd metatarsal shafts. A correction may need to be applied if metatarsus adductus is also present (i.e. if the second metatarsal is also medially deviated), as this will artificially reduce the intermetatarsal angle 6.

The normal range of the intermetatarsal angle is less than 9° 1. An increased angle is associated with hallux valgus deformity, and correlates with hallux valgus severity as follows 9:

  • mild: 9-11°
  • moderate: 12-17°
  • severe: ≥18°

Foot pronation can increase the intermetatarsal angle by ~3° 5.

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