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Congenital Abnormalities

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Syndactyly - Pseudo-Syndactyly » Fingers Q70.-


Syndactyly: Two or more fused digits.
Specify -Affected Limbs (Hand and / or foot. Right, Left, Bilateral) and fused Digits (1 and 2, 2 and 3, etc).
Pseudo-Syndactyly: or fenestrated syndactyly: dígits fused at their tips and separated at their bases.
ICD10 subdivides syndactylies by affected limb, in upper or lower, and by fusion of soft tissue only or of phalanges as well. Although this criterium may be clinically useful, it is irrelevant from a dysmorphological standpoint, and only requires identification of the fused fingers.
Information may be added about the fusion being complete (up to the fingertips) or incomplete.
Soft tissue or bony syndactylies can easily be clinically distinguished by means of a simple semiological maneuver, which however can be hindered due to the small size of the newborn´s hands and feet.
By taking two adjacent metacarpals/ metatarsals between thumb and index finger and moving them alternatively along their axes, one upward (proximal), the other downward (distal), the examiner can determine if they move independently of each other or if they are fused. Biesecker et al, 2009.
Syndactyly must not be confounded with pseudo-syndactylies, which are the result of aseptic necrosis and scarring due to intra uterine band constriction [Q79.8], leading to fenestrated syndactylies: the fingertips are fused but their roots are not, and considered as an embryological absurd, since the direction of interdigital web apoptosis runs from distal to proximal.
Image 1
Finger soft tissue syndactyly [Q70.1].
1. Fusion of fingers 2-3-4-5; incomplete, with webbing.
2 . Fusion of fingers 3-4. Overriding fingers 2 and 3, simulate a fenestrated syndactyly.
3 . Fusion of fingers 2-3-4-5. incomplete, with webbing.
Image 5
A case of fenestrated syndactyly or pseudo-syndactyly due to intra uterine band constriction.