title: Mapping the articular contact area of the long head of the biceps tendon on the humeral head.
abstract: The purpose of this investigation was to calculate the contact surface area of the long head of the biceps (LHB) in neutral position and abduction. We sought to determine whether the LHB articulates with the humeral head in a consistent pattern comparing articular contact area in neutral position and abduction. Eleven fresh frozen matched cadaveric shoulders were analyzed. The path of the biceps tendon on the articular surface of the humeral head and the total articular surface were digitized using a MicronTracker 2 H3-60 three-dimensional optical tracker. Contact surface area was significantly less in abduction than in neutral position (P = 0.002) with a median ratio of 41% (36%, 47.5%). Ratios of contact area in neutral position to full articular surface area were consistent between left and right shoulders (rho = 1, P = 0.017) as were ratios of abduction area to full articular surface area (rho = 0.97, P = 0.005). The articular contact surface area is significantly greater in neutral position than abduction. The ratios of articular contact surface areas to total humeral articular surface areas have a narrow range and are consistent between left and right shoulders of the same cadaver.
authors.affiliation: Vanderbilt Sports Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA ; Vanderbilt Orthopaedic Institute, 1211 Medical Center Drive, 4200 MCE South Tower, Nashville, TN 37232, USA.
authors.forename: Brent J
authors.initials: BJ
authors.lastname: Morris
authors.affiliation: Vanderbilt Sports Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
authors.forename: Ian R
authors.initials: IR
authors.lastname: Byram
authors.affiliation: Vanderbilt University School of Engineering, Vanderbilt University, Nashville, TN 37235, USA.
authors.forename: Ray A
authors.initials: RA
authors.lastname: Lathrop
authors.affiliation: University of Wisconsin Sports Medicine, University of Wisconsin Health, Madison, WI 53792, USA.
authors.forename: Warren R
authors.initials: WR
authors.lastname: Dunn
authors.affiliation: Vanderbilt Sports Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
authors.forename: John E
authors.initials: JE
authors.lastname: Kuhn