title: MR imaging of the quadriceps tendon: normal layered configuration and its importance in cases of tendon rupture.
abstract: OBJECTIVE
  The quadriceps tendon is a multilayered structure with separate layers arising from different muscle groups. We examined this layered configuration on MR images to determine if it is relevant in the evaluation of the traumatized quadriceps tendon.
  
  
  METHODS
  Sagittal and axial T1-weighted MR images of 52 knees with normal tendons were reviewed to determine the number and the muscle origins of these layers. Five knees with traumatized quadriceps tendons were imaged with T1 and T2 weighting to determine the relationship between the layered configuration and the injury.
  
  
  RESULTS
  All the normal quadriceps tendons had a laminated appearance with either four (6%), three (56%), or two (30%) layers. In 8%, the laminations were barely perceptible. The site of origin of each layer was consistent, and each favored a given muscle. The superficial layer originated from the posterior fascia of the rectus femoris muscle, and the deep layer originated from the anterior fascia of the midline vastus intermedius muscle. The middle layer(s) arose from the deep fascia separating the vastus medialis and the vastus lateralis muscles from the vastus intermedius muscle. When only two layers were present, the middle layer merged with the superficial and deep layers. In the injured tendon, complete rupture produced transection of all the layers. Incomplete ruptures were seen as focal discontinuities of individual layers; other layers remained intact.
  
  
  CONCLUSIONS
  The existence of a layered configuration of the quadriceps tendon is significant in the MR examination of partial ruptures. It can help not only in detecting and localizing injuries but also in determining appropriate treatment based on the number or thickness of injured layers.
authors.affiliation: Department of Radiology, Medical College of Ohio, Toledo 43699.
authors.forename: J
authors.initials: J
authors.lastname: Zeiss
authors.forename: S R
authors.initials: SR
authors.lastname: Saddemi
authors.forename: N A
authors.initials: NA
authors.lastname: Ebraheim
mesh_terms: D005260:Female; D006801:Humans; D007717:Knee; D008279:Magnetic Resonance Imaging; D008297:Male; D012421:Rupture; D013708:Tendon Injuries / Q000175:diagnosis*; D013710:Tendons / Q000033:anatomy & histology*