title: Functional anatomy of the lateral collateral ligament of the elbow.
abstract: BACKGROUND
  The aim of this study was to analyze the functional anatomy of the lateral collateral ligament complex (LCLC) and the surrounding forearm extensors.
  
  
  METHODS
  Using 81 human cadaveric upper extremities, the anatomy of the forearm extensors-especially the anconeus, supinator and extensor carpi ulnaris (ECU)-was analyzed. After removal of aforementioned extensors the functional anatomy of the LCLC was analyzed. The origin of the LCLC was evaluated for isometry. The insertion types of the lateral ulnar collateral ligament (LUCL) were analyzed and classified.
  
  
  RESULTS
  The ECU runs parallel to the RCL to dynamically preserve varus stability. The supinator and anconeus muscle fibers coalesce with the LCLC and lengthen during pronation. The anconeus fibers run parallel to the LUCL in full flexion. The LCLC consists of the annular ligament (AL) and the isometric radial collateral ligament (RCL). During elbow flexion, its posterior branches (LUCL) tighten while the anterior branches loosen. When performing a pivot shift test, the loosened LUCL fibers do not fully tighten in full extension. The LUCL inserts along with the AL at the supinator crest. Three different insertion types could be observed.
  
  
  CONCLUSIONS
  The LUCL represents the posterior branch of the RCL rather than a distinct ligament. It is non-isometric and lengthens during elbow flexion. The RCL was found to be of vital importance for neutralization of posterolateral rotatory forces. Pronation of the forearm actively stabilizes the elbow joint as the supinator, anconeus and biceps muscle work in unison to increase posterolateral rotatory stability.
authors.affiliation: Center for Orthopedic and Trauma Surgery, University Medical Center of Cologne, Kerpener Straße 62, 50937, Cologne, Germany. michael.hackl@uk-koeln.de.|Cologne Center for Musculoskeletal Biomechanics, Medical Faculty, University of Cologne, Cologne, Germany. michael.hackl@uk-koeln.de.
authors.forename: M
authors.initials: M
authors.lastname: Hackl
authors.affiliation: Center for Orthopedic and Trauma Surgery, University Medical Center of Cologne, Kerpener Straße 62, 50937, Cologne, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Bercher
authors.affiliation: Center for Orthopedic and Trauma Surgery, University Medical Center of Cologne, Kerpener Straße 62, 50937, Cologne, Germany.|Cologne Center for Musculoskeletal Biomechanics, Medical Faculty, University of Cologne, Cologne, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Wegmann
authors.affiliation: Center for Orthopedic and Trauma Surgery, University Medical Center of Cologne, Kerpener Straße 62, 50937, Cologne, Germany.|Cologne Center for Musculoskeletal Biomechanics, Medical Faculty, University of Cologne, Cologne, Germany.
authors.forename: L P
authors.initials: LP
authors.lastname: Müller
authors.affiliation: Center for Orthopedic and Trauma Surgery, University Medical Center of Cologne, Kerpener Straße 62, 50937, Cologne, Germany.|Cologne Center for Musculoskeletal Biomechanics, Medical Faculty, University of Cologne, Cologne, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Dargel
mesh_terms: D002102:Cadaver; D017885:Collateral Ligaments / Q000033:anatomy & histology*; D004550:Elbow; D004551:Elbow Joint / Q000033:anatomy & histology* / Q000502:physiology; D005542:Forearm / Q000033:anatomy & histology* / Q000502:physiology; D006801:Humans; D018482:Muscle, Skeletal / Q000033:anatomy & histology* / Q000502:physiology; D011403:Pronation; D016059:Range of Motion, Articular / Q000502:physiology; D034941:Upper Extremity
keywords: Elbow; Functional anatomy; LCL; LUCL; Lateral collateral ligament; RCL