title: Effects of biceps tension and superior humeral head translation on the glenoid labrum.
abstract: We sought to understand the effects of superior humeral head translation and load of the long head of biceps on the pathomechanics of the superior glenoid labrum by predicting labral strain. Using micro-CT cadaver images, a finite element model of the glenohumeral joint was generated, consisting of humerus, glenoid bone, cartilages, labrum, and biceps tendon. A glenohumeral compression of 50 N and biceps tensions of 0, 22, 55, and 88 N were applied. The humeral head was superiorly translated from 0 to 5 mm in 1-mm increments. The highest labral strain occurred at the interface with the glenoid cartilage and bone beneath the origin of the biceps tendon. The maximum strain was lower than the reported failure strain. The humeral head motion had relatively greater effect than biceps tension on the increasing labral strain. This supports the mechanistic hypothesis that superior labral lesions result mainly from superior migration of the humeral head, but also from biceps tension
authors: School of Kinesiology, University of Michigan, Ann Arbor, Michigan; Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan.
authors: Eunjoo
authors: E
authors: Hwang
authors: James E
authors: JE
authors: Carpenter
authors: Richard E
authors: RE
authors: Hughes
authors: Mark L
authors: ML
authors: Palmer
mesh_terms: D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D002102:Cadaver; D003198:Computer Simulation; D020342:Finite Element Analysis; D061165:Glenoid Cavity / Q000502:physiology; D006801:Humans; D058430:Humeral Head / Q000502:physiology*; D006811:Humerus / Q000502:physiology; D008297:Male; D008953:Models, Anatomic; D009038:Motion; D018482:Muscle, Skeletal / Q000502:physiology*; D017006:Rotator Cuff / Q000502:physiology; D012782:Shoulder / Q000502:physiology; D012785:Shoulder Joint / Q000502:physiology*; D013710:Tendons / Q000502:physiology; D055114:X-Ray Microtomography
keywords: FE; biceps; labrum; rotator cuff; shoulder