title: Muscle activation patterns in snapping triceps syndrome.
abstract: OBJECTIVE
  To compare the muscle activation pattern in subjects with and without "snapping triceps syndrome" (dislocation of the medial head of the triceps and ulnar nerve over the medial epicondyle).
  
  
  METHODS
  Controlled study.
  
  
  METHODS
  Biomechanics laboratory.
  
  
  METHODS
  Eight male subjects (9 elbows), with symptomatic snapping triceps and 9 male controls.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Activation pattern of the 3 triceps heads during active elbow extension at 0 degrees , 45 degrees , 70 degrees , 90 degrees , and 115 degrees of flexion, recorded by fine-wire electromyography.
  
  
  RESULTS
  There were no significant differences between subjects and controls in the firing pattern of the triceps heads. The medial head fired first in 6 of 9 symptomatic elbows and in 7 of 9 controls at 90 degrees of flexion, and in 6 of 9 elbows of both subjects and controls at 115 degrees of flexion, positions where snapping typically occurs. There was no significant difference between the groups as to how often the medial head fired maximally.
  
  
  CONCLUSIONS
  This study suggests the firing pattern of the triceps heads may not contribute to the pathogenesis of this syndrome. Rather, the authors believe the anatomic position of the medial head causes it to dislocate over the medial epicondyle, often resulting in ulnar neuritis.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Andrea J
authors.initials: AJ
authors.lastname: Boon
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Spinner
authors.forename: Kathie A
authors.initials: KA
authors.lastname: Bernhardt
authors.forename: Scott R
authors.initials: SR
authors.lastname: Ross
authors.forename: Kenton R
authors.initials: KR
authors.lastname: Kaufman
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D004551:Elbow Joint / Q000503:physiopathology*; D004576:Electromyography; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D018482:Muscle, Skeletal / Q000503:physiopathology*; D016059:Range of Motion, Articular / Q000502:physiology; D013577:Syndrome; D014459:Ulnar Nerve / Q000503:physiopathology*