Diagnosing the<unk>  is difficult in the first three to four months of life, as it is normal when the<unk>  is clutched into the palm in these first months. Diagnoses that cause the same flexion or adduction abnormalities of the<unk>  are: *<unk>  * Congenital Trigger<unk>  (flexion of the interphalangeal joint) - Trigger finger * Spasticity: overstimulation of muscles Syndrome associated flexion-adduction of the<unk> : * Freeman–Sheldon syndrome (a congenital, heritable affection of the face, the hands, the feet and some joints) * Distal arthrogryposis * MASA syndrome * X-linked hydrocephalus * Adducted<unk>  syndrome * Waardenburg syndrome * Whistling face syndrome (Freeman–Sheldon syndrome) * Digitotalar dysmorphism * Multiple pterygium syndrome Classification There are a few different classifications conceived to categorize the spectrum of variety of<unk> . In literature, X classifications have been described for<unk><unk> . The two most relevant of the existing classifications, to our opinion, are the classifications of McCarrol and Tjuyuguchi et al. The most global format is the classification of McCarrol, which divides the<unk> s into two groups. Group I includes the supple<unk><unk> , when the<unk>  is only passively correctable. While complex<unk><unk> s,<unk> s which cannot be moved neither passively or actively, belong to group II. Tjuyuguchi et al. designed a classification existing of three groups: * Group I: The supple<unk><unk> , where the<unk>  is passively abductable and extendable against the resistance of<unk>  flexors, without other digital anomalies. * Group II: The<unk><unk>  with hand contractures, where the<unk>  is not passively extendable and abductable, with or without other digital anomalies. * Group III: The<unk><unk>  which is associated with arthrogryposis.
Congenital clasped thumb
Congenital trigger thumb
Cenani–Lenz syndactylism
Congenital contractural arachnodactyly
Camptodactyly
Ectrodactyly
Synpolydactyly
Radial aplasia