Polydactyly

Polydactyly is a congenital condition in which a person or animal has more than the usual number of fingers or toes. The extra digit may be fully formed or rudimentary.

Limb development: The embryonic processes that form the bones, muscles, and other structures of the arms and legs. Polydactyly arises when patterning during limb formation produces an additional digit.
Preaxial polydactyly: Polydactyly in which an extra digit forms on the thumb or big-toe side of a limb. This is the radial or tibial-sided pattern of extra digits.
Prenatal ultrasound: An imaging method that uses sound waves to examine a fetus during pregnancy. It can identify polydactyly before birth and assess whether other visible anomalies are present.
Syndactyly: A congenital condition in which two or more fingers or toes are joined together. Polydactyly adds a digit, whereas syndactyly joins digits that are present.
Johann Friedrich Meckel: A German anatomist and physician known for foundational work in comparative anatomy and congenital malformations. His name is associated with Meckel syndrome, which can include postaxial polydactyly.
Digit patterning: The developmental process that establishes the number, identity, and arrangement of digits in a limb. Changes in digit patterning can produce the extra fingers or toes characteristic of polydactyly.
Postaxial polydactyly: Polydactyly in which an extra digit forms on the little-finger or little-toe side of a limb. This is the ulnar or fibular-sided pattern of extra digits.
Radiography: Medical imaging that uses X-rays to show internal structures, especially bones. X-rays reveal whether an extra digit has bones and how it connects to the hand or foot.
Oligodactyly: A congenital condition in which a hand or foot has fewer than the usual number of digits. It contrasts with polydactyly by involving a reduced rather than increased digit count.
David Weyhe Smith: An American pediatrician and medical geneticist who helped establish the field of clinical dysmorphology. His work shaped the clinical classification of congenital patterns that may include polydactyly.

Linked from 10 pages