title: Fibre bundles in the human extensor carpi ulnaris tendon are arranged in a spiral.
abstract: The extensor carpi ulnaris musculotendinous unit has important agonist and antagonist action in wrist motion, including the dart-throwing action, and is a dynamic stabilizer of the distal radioulnar joint during forearm rotation. Despite its functional and clinical importance, little is known about its internal structure. Investigation of the ultrastructure of the human extensor carpi ulnaris (ECU) tendon was undertaken using plane polarized light microscopy and microcomputer tomography with 3D reconstruction. The study demonstrates that the tendon comprises fibre bundles (fascicles) approximately 0.1 mm in diameter that are arranged in a gradual spiral. The spiralling fibres make an angle of 8º to the longitudinal axis of the tendon. The spiral structure of the human ECU tendon has important biomechanical implications, allowing fascicular sliding during forearm rotation. The observed features may prevent injury.
authors.affiliation: Plastic Surgery Department, University Hospital of South Manchester NHS Foundation Trust, Wythenshawe, Manchester, UK.
authors.forename: N S
authors.initials: NS
authors.lastname: Kalson
authors.forename: P S C
authors.initials: PS
authors.lastname: Malone
authors.forename: R S
authors.initials: RS
authors.lastname: Bradley
authors.forename: P J
authors.initials: PJ
authors.lastname: Withers
authors.forename: V C
authors.initials: VC
authors.lastname: Lees
mesh_terms: D001696:Biomechanical Phenomena; D003094:Collagen; D005542:Forearm / Q000502:physiology; D006801:Humans; D008859:Microscopy, Polarization; D008875:Middle Aged; D009412:Nerve Fibers / Q000648:ultrastructure*; D012399:Rotation; D013710:Tendons / Q000648:ultrastructure*; D020858:Tissue and Organ Harvesting; D014955:Wrist Joint
chemical_list: D003094:Collagen