title: Smaller insertion area and inefficient mechanics of the gluteus medius in females.
abstract: OBJECTIVE
  Tears of the gluteus medius are most prevalent in middle-aged females. Recently, focus has been placed on diagnosis and treatment of tears, but an explanation for the increased prevalence still eludes researchers. We compared the area of insertion of the gluteus medius on the femur as well as three separate moment arm measures between males and females to determine if a smaller insertion area and/or decreased hip efficiency existed in females.
  
  
  METHODS
  The gluteus medius was dissected on 37 embalmed cadaveric hips (23 M, 14 F; mean age 66.4 years) to expose its insertion on the femur, which was then outlined. Three-dimensional scans were taken of each insertion, and area measurements calculated. Reference points were placed on analogous structures within each hip, and moment arms were calculated using the x, y, z coordinates of these points. The gluteus medius insertion and three moment arm lengths were compared between the genders.
  
  
  RESULTS
  Gluteus medius insertion area was found to be smaller in females (M 602.35 ± 116.01 mm, F 534.96 ± 98.60 mm, p = 0.034). The gluteal moment arms were also shorter in females (GMA1, M 69.87 ± 7.03 mm, F 63.22 ± 4.64 mm, p = 0.001) (GMA2, M 83.18 ± 6.69 mm, F 75.06 ± 6.23 mm, p = 0.000) with pelvic moment arms being comparable between the genders. Stature and age were not found to influence these outcomes.
  
  
  CONCLUSIONS
  Our results suggest that in an equally massive male and female, the female will place greater mechanical demands on the gluteus medius, due to decreased efficiency as well as a relatively smaller insertion area.
authors.affiliation: Kansas City University of Medicine and Biosciences, 1750 Independence Ave, Kansas City, MO, 64106, USA, dustinwoyski@gmail.com.
authors.forename: Dustin
authors.initials: D
authors.lastname: Woyski
authors.forename: Anthony
authors.initials: A
authors.lastname: Olinger
authors.forename: Barth
authors.initials: B
authors.lastname: Wright
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006615:Hip / Q000033:anatomy & histology* / Q000502:physiology; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000033:anatomy & histology* / Q000293:injuries / Q000502:physiology; D055815:Young Adult