Large polygonal leg

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Wrist (schematic):
A – H = carpal bones
  • A scaphoid bone ( scaphoid bone )
  • B moon bone ( os lunatum )
  • C triangular bone ( os triquetrum )
  • D pea bone ( os pisiforme )
  • E large polygonal bone ( trapezium )
  • F small polygonal bone ( os trapezoideum )
  • G headbone ( os capitatum )
  • H hook bone ( os hamatum )
    • 1 spoke ( radius )
    2 ulna ( ulna )
    3 metacarpal bones ( ossa metacarpalia )
    Drawing of the left large polygonal bone showing the articular surfaces

    The large trapezoid ( lat. Trapezium , Os carpal primum ) is one of the eight carpal bones and the distal part ( distal ) series of short bones to.

    It can be easily felt through the skin when the back of the hand is pulled up ( dorsiflexion), because it has a cusp there ( tuberculum ossis trapezii ). Towards the middle ( medial ) there is a furrow ( sulcus musculi flexoris carpi radialis ) for the tendon of the hand flexor ( flexor carpi radialis muscle ). Far from the body ( distal ) there is a saddle-shaped joint surface for the first metacarpal bone ( Os metacarpale I ), with which the large polygon forms the thumb saddle joint . Towards the middle, the large polygonal bone is connected to the small polygonal bone ( os trapezoideum ). Between the joint surface further away from the body and the joint surface directed towards the center there is an additional, small joint surface for the second metacarpal bone ( os metacarpale II ). Close to the body, the large polygonal bone is articulated with the scaphoid bone ( os scaphoideum ) .

    literature

    • W. Platzer: Pocket Atlas of Anatomy, Volume 1 - Musculoskeletal System . Thieme Verlag, Stuttgart 2005, p. 126. ISBN 3-13-492009-3