title: MRI and gross anatomy of the iliopsoas tendon complex.
abstract: OBJECTIVE
  The objective was to explain the anatomic basis of a longitudinal cleft of increased signal in the iliopsoas tendon seen on hip MR arthrograms.
  
  
  METHODS
  A prospective review of 20 MR hip arthrograms was performed using standard and fat-suppressed T1-weighted images to establish whether or not the cleft was composed of fatty tissue and to define the anatomy of the iliopsoas tendon complex. Three cadaver dissections of the hip region were then performed for anatomic correlation.
  
  
  RESULTS
  Fourteen out of 20 MR hip arthrograms demonstrated a longitudinal cleft of increased T1 signal adjacent to the iliopsoas tendon, which suppressed on frequency selective fat-suppressed images, indicating fatty composition. Gross anatomic correlation demonstrated this fatty cleft to represent a fascial plane adjacent to the iliopsoas tendon, in one case separating the iliopsoas tendon medially from a thin intramuscular tendon within the lateral portion of the iliacus muscle. Also noted was a direct muscular insertion of the lateral portion of the iliacus muscle onto the anterior portion of the proximal femoral diaphysis in all 3 cadavers.
  
  
  CONCLUSIONS
  The anatomy of the iliopsoas tendon complex is more complicated than typically illustrated and includes the iliopsoas tendon itself attaching to the lesser trochanter, the lateral portion of the iliacus muscle attaching directly upon the anterior portion of the proximal femoral diaphysis, and a thin intramuscular tendon within this lateral iliacus muscle that is separated from the iliopsoas tendon by a cleft of fatty fascia that accounts for the MRI findings of a cleft of increased T1 signal.
authors.affiliation: Section of Musculoskeletal Radiology, Department of Radiology, Cleveland Clinic, 9500 Euclid Avenue, A21, Cleveland, OH 44195, USA. polstej@ccf.org
authors.forename: Joshua M
authors.initials: JM
authors.lastname: Polster
authors.forename: Mohamed
authors.initials: M
authors.lastname: Elgabaly
authors.forename: Ho
authors.initials: H
authors.lastname: Lee
authors.forename: Alison
authors.initials: A
authors.lastname: Klika
authors.forename: Richard
authors.initials: R
authors.lastname: Drake
authors.forename: Wael
authors.initials: W
authors.lastname: Barsoum
mesh_terms: D001175:Arthrography / Q000379:methods; D002102:Cadaver; D003287:Contrast Media / Q000008:administration & dosage; D019786:Gadolinium DTPA; D006621:Hip Joint / Q000033:anatomy & histology / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008488:Medical Illustration; D010146:Pain / Q000209:etiology; D011446:Prospective Studies; D013708:Tendon Injuries / Q000175:diagnosis*; D013710:Tendons / Q000002:abnormalities / Q000033:anatomy & histology / Q000473:pathology*
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA