Mapping the articular contact area of the long head of the biceps tendon on the humeral head.

Brent J Morris,Warren R Dunn,Ian R Byram,Ray A Lathrop,John E Kuhn

doi:10.1155/2014/814721

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.

Highlights

The long head of the biceps (LHB) tendon arises from the posterior superior glenoid labrum and the supraglenoid tubercle and is ensheathed by synovial lining allowing it to be intra-articular yet extrasynovial [1, 2]
It emerges from the glenohumeral joint in the bicipital groove and provides glenohumeral stability acting as a stabilizer and depressor of the humeral head while elevating the labrum [3,4,5,6,7]
Pain and stiffness following superior labrum, anterior and posterior lesion (SLAP) repairs may be associated with a humeral head abrasion under the articular portion of the biceps tendon caused by increased bicepshumeral head contact pressure [11]

Summary

Introduction

The long head of the biceps (LHB) tendon arises from the posterior superior glenoid labrum and the supraglenoid tubercle and is ensheathed by synovial lining allowing it to be intra-articular yet extrasynovial [1, 2]. It emerges from the glenohumeral joint in the bicipital groove and provides glenohumeral stability acting as a stabilizer and depressor of the humeral head while elevating the labrum [3,4,5,6,7]. Pain and stiffness following superior labrum, anterior and posterior lesion (SLAP) repairs may be associated with a humeral head abrasion under the articular portion of the biceps tendon caused by increased bicepshumeral head contact pressure [11]

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Conclusion