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Lunate

       

  - Acute Ligament Tear - Repair Technique
  - Blood Supply to the Wrist
  - Carpal Instability
  - Differential Diagnosis
  - Kienbock's disease
  - Luno-Triquetral Coalition
  - Perilunate Dislocations
  - Scapholunate Instability
  - Vascularity of the Lunate
  - X-ray findings

- Discussion:
    - lunate articulates proximally w/ radius and distally w/ capitate;
    - it has large volar surface, & is displaced volarward w/ forced dorsiflexion of the wrist;
    - most frequently dislocated carpal bone;
    - w/ flexion capitate slides out from under lunate to create fullness where the capitate depression has been;

- Radiographs:
    - lunate, capitate, and the base of the 3rd metacarpal are in line w/each other & is covered by base of ECRB;
    - colinear alignment of: radius, lunate, capitate, & 3rd metacarpal;
    - deviation of more than 15 deg either way between the links of chain may be viewed as lax, diseased, or damaged;

- Exam:
    - it is palpable just distal to radial tubercle;
    - w/ flexion and extension lunate/capitate articulation may be felt;
    - tenderness of dorsal lunate may suggest Keinbock's dz, while more ulnar tenderness suggests tears of TFC or lunotriquetral ligament;
    - knowing position of ECU & ulnar styloid helds to differentiate ECU tendinitis from distal radioulnar problems


Limited open reduction of the lunate facet in comminuted intra-articular fractures of the distal radius.

Difficult wrist fractures. Perilunate fracture-dislocations of the wrist.

Late treatment of a dorsal transscaphoid, transtriquetral perilunate wrist dislocation with avascular changes of the lunate.