Anatomical classification

Cleft hand may be classified according to the increasing extent of the anatomical deficit. Additionally, within any group the letters s or p may denote digits that exhibit syndactyly or polydactyly, respectively. Types 1 to 3 have a central V-shaped cleft but additionally:

• type 1: absent middle finger
• type 2: absent middle and index fingers
• type 3: absent middle, index and ring fingers

Type 4 has an absence of radial digits: thumb, index and middle fingers. Type 5 is monodactylous with only little finger remaining.

An alternative anatomical classification system was described by Sandzen(1) in 1985. Types 1 and 3 are now considered as cleft hand whereas type 2 is increasingly recognised as a form of symbrachydactyly:

• type 1:
  • often bilateral
  • involves the foot
  • usually familial
  • one or more central rays absent
  • cone shape defect extends proximally into the metacarpals
• type 2:
  • atypical
  • usually unilateral
  • does not involve the feet
  • sporadic, no inheritance pattern
  • U-shaped cleft
  • partial or complete absence of metacarpals
  • hypoplastic thumb and little finger
• type 3:
  • one to three rays are missing
  • syndactyly and polydactyly

Ref: (1) Sandzen SC (1985). Hand Clin 1: 483-498.