page_title: Carpal coalition
section_title: Subtypes
hierarchical_section_title: Carpal coalition / Subtypes
caption_attribution_description: Deutsch: Karpale Koalition: Hier seltener Fall einer Fusion von Os capitatum und Os trapezoideum. Ob die Fusion komplett knöchern ist, kann anhand dieser einen Aufnahme nicht sicher entschieden werden. Zufallsbefund bei Frakturausschluss.
context_page_description: Carpal coalition is the abnormal fusion of two or more carpal bones when they fail to segment during intrauterine development. First described by Eduard Sandifort in 1779, carpal coalitions are often an isolated issue which connect two carpal bones in the same row of the wrist. These issues are congenital and occur at various rates throughout the population.
context_section_description: The lunate and triquetral bones are the most common carpal bones to fuse together, resulting in a lunotriquetral coalition in 1% of people. 60% of patients with a lunotriquetral coalition will have it bilaterally. Among isolated incidents the capitate and hamate bones are the next most common to fuse followed by the pisiform-triquetrum, trapezium-trapezoid, scaphoid-capitate, and triquetrum-hamate.
  Carpal coalitions may further be divided into four subtypes:
  Type 1 - incomplete fusion with pseudoarthrosis
  Type 2 - fusion with a "notch" between the fused bones
  Type 3 - complete fusion
  Type 4 - complete fusion with other anomalies present
caption: An example of a coalition between the trapezoid and capitate carpal bones
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