title: Atypical hip impingement.
abstract: OBJECTIVE
  This article summarizes how atypical forms of hip impingement can be assessed with radiographs, CT, and MRI.
  
  
  CONCLUSIONS
  Subspine impingement, ischiofemoral impingement, and iliopsoas impingement are atypical forms of hip impingement and are less common than classic femoroacetabular impingement. Additional forms of atypical impingement, such as abnormal femoral antetorsion, abnormal pelvic and acetabular tilt, and extreme hip motion, can occur combined with classic femoroacetabular impingement or as separate entities.
authors: Department of Radiology, Orthopedic University Hospital Balgrist, Forchstrasse 340, Zurich 8008, Switzerland. reto.sutter@balgrist.ch
authors: Reto
authors: R
authors: Sutter
authors: Christian W A
authors: CW
authors: Pfirrmann
mesh_terms: D001696:Biomechanical Phenomena; D003937:Diagnosis, Differential; D057925:Femoracetabular Impingement / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D014057:Tomography, X-Ray Computed