title: Effect of simultaneous stretching of the wrist and finger extensors for lateral epicondylitis: a gross anatomical study of the tendinous origins of the extensor carpi radialis brevis and extensor digitorum communis.
abstract: BACKGROUND
  Pulling the wrist into flexion with the elbow in extension and forearm in pronation has been used as the stretching technique of wrist extensors for lateral epicondylitis. Simultaneous stretching of the fingers in addition to the wrist flexion has also been applied. However, the mechanism of this simultaneous stretching has not been clarified. This study is designed to clarify the mechanism underlying this simultaneous stretching technique based on the anatomical features of the origins of the extensor carpi radialis brevis (ECRB) and extensor digitorum communis (EDC).
  
  
  METHODS
  Thirty-nine arms from formalin-embalmed Japanese human specimens were dissected. The features of the origins of the ECRB and EDC were macroscopically observed, and the locations of each origin on the lateral epicondyle were measured.
  
  
  RESULTS
  The ECRB had a long and wide, purely tendinous origin which originated from the anterior slope of the lateral epicondyle. The tendinous origin of the index finger of the EDC (EDC-IF) arose from the posterior aspect of the ECRB tendinous origin, with a coexisting muscular portion observed at the level of the proximal forearm. The middle finger of the EDC (EDC-MF) had a short tendinous origin with an associated muscular portion and originated proximo-laterally to the origin of the ECRB on the lateral epicondyle. In addition, the muscular origin of the EDC-MF arose on the superficial and posterior aspect of the ECRB tendinous origin. In contrast, the ring and little fingers of the EDC originated from the tendinous septum of the extensor digiti minimi and extensor carpi ulnaris, and had no connection with the ECRB tendinous origin.
  
  
  CONCLUSIONS
  On the basis of our anatomical findings, simultaneous stretching of the wrist extensors by wrist, index and middle fingers flexion could provide stretching force to both the tendinous origins of the ECRB and EDC through the EDC-IF and EDC-MF.
authors.affiliation: Department of Orthopaedic Surgery, Sapporo Medical University, South-1, West-16, Chuo-ku, Sapporo, 060-8556, Japan. rshirato@sapmed.ac.jp.
authors.forename: Rikiya
authors.initials: R
authors.lastname: Shirato
authors.affiliation: Department of Orthopaedic Surgery, Saiseikai Otaru Hospital, Otaru, Japan.
authors.forename: Takuro
authors.initials: T
authors.lastname: Wada
authors.affiliation: Department of Orthopedics, Health Science University of Hokkaido School of Rehabilitation Sciences, Ishikari, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Aoki
authors.affiliation: Department of Orthopaedic Surgery, Sapporo Medical University, South-1, West-16, Chuo-ku, Sapporo, 060-8556, Japan.
authors.forename: Kousuke
authors.initials: K
authors.lastname: Iba
authors.affiliation: Department of Orthopaedic Surgery, Sapporo Medical University, South-1, West-16, Chuo-ku, Sapporo, 060-8556, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Kanaya
authors.affiliation: The 2nd Department of Anatomy, Sapporo Medical University, Sapporo, Japan.
authors.forename: Mineko
authors.initials: M
authors.lastname: Fujimiya
authors.affiliation: Department of Orthopaedic Surgery, Sapporo Medical University, South-1, West-16, Chuo-ku, Sapporo, 060-8556, Japan.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Yamashita
mesh_terms: D000328:Adult; D002102:Cadaver; D004210:Dissection; D005384:Finger Joint / Q000033:anatomy & histology* / Q000502:physiology; D006801:Humans; D008875:Middle Aged; D052580:Muscle Stretching Exercises / Q000379:methods*; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000502:physiology; D012680:Sensitivity and Specificity; D013710:Tendons / Q000033:anatomy & histology*; D013716:Tennis Elbow / Q000503:physiopathology / Q000534:rehabilitation*; D034941:Upper Extremity; D014955:Wrist Joint / Q000033:anatomy & histology* / Q000502:physiology