Moon leg

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Drawing of the left lunar bone showing the articular surfaces
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 )

    The crescent moon leg ( lat. Lunate or carpal intermedium ) is one of the eight carpal bones and the proximal part ( proximal ) series of these short bones on.

    It is close to the body ( proximal ) connected to the spoke ( radius ) and the joint disc ( discus articularis ). To the middle ( medial ) it communicates with the triangular leg ( triquetrum ), side ( lateral ) and the navicular bone ( scaphoid ) and distally ( distally ) to the capitate bone ( Os capitatum ) and the hook leg ( hamate ) in articulated connection.

    In dogs , the moon bone is fused with the scaphoid bone to form the os carpi intermedioradiale .

    clinic

    X-ray perilunar dislocation

    The moon bone can be involved in osteoarthritis of the wrist. Rarely does a fall lead to a "perilunar dislocation ", in which the remaining carpal bones tear off the lunar bone, which remains firmly attached to the radius and ulna. As a result of an accident or caused by rheumatism, ligaments can be destroyed with a “scapholunal dissociation” in which a typical gap between the scaphoid and lunar bone can be seen on X-rays .

    Because of the cartilage coating on almost all sides, the vascular supply to the lunar bone is precarious and bone necrosis can occur. This is known for the lunar bone as Kienböck's disease or lunate malacia and occurs particularly in vibration trauma (jackhammer) or in an anatomical variation with a shortened ulna (ulna minus variant).

    literature

    • W. Platzer: Pocket Atlas of Anatomy . Volume 1 - musculoskeletal system . Thieme Verlag, Stuttgart 2005, p. 126. ISBN 3-13-492009-3
    • Franz-Viktor Salomon: Bony skeleton . In: Franz-Viktor Salomon et al. (Ed.): Anatomy for veterinary medicine. 2nd ext. Edition. Enke-Verlag, Stuttgart 2008, ISBN 978-3-8304-1075-1 , pp. 37-110.