title: Blumensaat's line is not always straight: morphological variations of the lateral wall of the femoral intercondylar notch.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the morphological variations of the lateral wall of the femoral intercondylar notch.
  
  
  METHODS
  Fifty-two non-paired human cadaver knees were used. All soft tissues around the knee were resected except the ACL. The ACL was cut in the middle, and the femoral bone was cut at the most proximal point of the femoral notch parallel to the plane of the femoral bone shaft. The ACL was carefully dissected, and the periphery of the ACL insertion site was outlined on the femoral side. An accurate lateral view of the femoral condyle was photographed with a digital camera, and the images were downloaded to a personal computer. The morphological variations of Blumensaat's line, the height and area of the lateral wall of the femoral intercondylar notch and the size of the femoral ACL footprints were measured with Image J software.
  
  
  RESULTS
  Blumensaat's line exhibited three types of morphological variations. A straight line was observed in 19 knees (37 %) (straight type). A protrusion spanning less than half of the line was observed at the proximal part of Blumensaat's line in 10 knees (19 %) (small hill type). A protrusion spanning more than half of the line was observed at the proximal part of the line in 23 knees (44 %) (large hill type). In some knees with this large hill type variation, the appearance was similar to that of anterior spur. No significant differences between these three types were observed in either the height and area of the lateral wall of the femoral intercondylar notch or the area of the femoral ACL footprint.
  
  
  CONCLUSIONS
  In conclusion, Blumensaat's line has three types of morphological variations (straight, small hill and large hill types). For the clinical relevance, when ACL surgery is performed in knees with small or large hill type variations, surgeons should pay close attention to femoral tunnel evaluation and placement, especially for the use of Quadrant method. The grid placement of Quadrant method would be changed in the knees of these type variations.
authors: Department of Orthopaedic Surgery, Kamimoku Hot Springs Hospital, Minakami, Japan. sekaiwoseisu@yahoo.co.jp.|Department of Functional Morphology, Nihon University School of Medicine, Tokyo, Japan. sekaiwoseisu@yahoo.co.jp.
authors: Takanori
authors: T
authors: Iriuchishima
authors: Department of Orthopaedic Surgery, Nihon University Hospital, Tokyo, Japan.
authors: Keinosuke
authors: K
authors: Ryu
authors: Department of Functional Morphology, Nihon University School of Medicine, Tokyo, Japan.
authors: Shin
authors: S
authors: Aizawa
authors: Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors: Freddie H
authors: FH
authors: Fu
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001837:Body Weights and Measures; D002102:Cadaver; D004210:Dissection; D005260:Female; D005269:Femur / Q000033:anatomy & histology*; D006801:Humans; D007719:Knee Joint / Q000033:anatomy & histology*; D008297:Male
keywords: Anatomy; Anterior cruciate ligament; Blumensaat’s line; Intercondylar notch