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Polydactyly
Polydactyly (famously known as sixth finger and extra finger) is a birth defect that results in extra fingers or toes. The hands are more commonly involved than the feet. Extra fingers may be painful, affect self-esteem, or result in clumsiness.
It is associated with at least 39 genetic mutations. It may either present alone or with other defects. Cases may run in families. The underlying mechanism involves an error in limb bud formation during early development. Diagnosis may occur before birth via prenatal ultrasound as early as nine weeks. X-rays may be useful after a child is a year old. The opposite is oligodactyly (fewer fingers or toes).
Treatment varies from removal by cautery to more involved surgery. While putting a tight band around the base has been carried out, this is not typically recommended. If surgery is required, this is often done around two years of age. Occasionally multiple surgeries are required.
Polydactyly is present in about 4 to 12 per 10,000 newborns. It is the most common defect of the hands and feet. In the United States, Black people are more commonly affected than White people. The term is from Greek πολύς (polys) 'many' and δάκτυλος (daktylos) 'finger'.
In humans/animals this condition can present itself on one or both hands or feet. The extra digit is usually a small piece of soft tissue that can be removed. Occasionally it contains bone without joints; rarely it may be a complete functioning digit. The extra digit is most common on the ulnar (little finger) side of the hand, less common on the radial (thumb) side, and very rarely within the middle three digits. These are respectively known as postaxial (little finger), preaxial (thumb), and central (ring, middle, index fingers) polydactyly. The extra digit is most commonly an abnormal fork in an existing digit, or it may rarely originate at the wrist as a normal digit does. Polydactyly can be divided into three major types, which are discussed below, which depend on the location of the additional digit.
In 2019 it was found that in cases of polydactyly with a fully functional additional digit, muscles to control the extra digit may be duplicated, resulting in increased motor control that allows the patient to carry out certain tasks with one hand that would normally require two.
This is the most common situation, in which the extra digit is on the ulnar side of the hand, thus the side of the little finger. This can also be called postaxial polydactyly. It can manifest itself very subtly, for instance only as a nubbin on the ulnar side of the little finger, or very distinctly, as a fully developed finger. Most commonly, the extra finger is rudimentary, consisting of an end phalanx with a nail, and connected to the hand with a small skin pedicle. Mostly one neurovascular bundle can be identified, with no tendons present in the extra digit. In case of a fully developed extra finger, the duplication usually presents itself at the level of the metacarpophalangeal joint. A triplication of the little finger is very rare. Ulnar polydactyly occurs ten times more often in African populations. The incidence in Caucasians is reported as 1 in 1,339 live births, compared with 1 in 143 live births in Africans. Ulnar polydactyly is also often part of a syndrome. In patients with African ancestry ulnar polydactyly mostly occurs isolated, whereas the presentation in Caucasians is often associated with a syndrome, though in a retrospective review, only 4 of 37 cases of ulnar polydactyly in Caucasians were syndromic.
This is a less common situation, in which the affectation is on the side of the hand towards the thumb. Radial polydactyly refers to the presence of an extra digit (or extra digits) on the radial side of the hand. It is most frequent in Indian populations and it is the second most common congenital hand disorder. The incidence of radial polydactyly is reported as 1 in every 3,000 live births. The clinical features of radial polydactyly will depend upon the extent of duplication. Radial polydactyly varies from a barely visible radial skin tag to complete duplication. Thumb polydactyly varies from barely visible broadening of the distal phalanx to full duplication of the thumb including the first metacarpal. Radial polydactyly is frequently associated with several syndromes.
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Polydactyly AI simulator
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Polydactyly
Polydactyly (famously known as sixth finger and extra finger) is a birth defect that results in extra fingers or toes. The hands are more commonly involved than the feet. Extra fingers may be painful, affect self-esteem, or result in clumsiness.
It is associated with at least 39 genetic mutations. It may either present alone or with other defects. Cases may run in families. The underlying mechanism involves an error in limb bud formation during early development. Diagnosis may occur before birth via prenatal ultrasound as early as nine weeks. X-rays may be useful after a child is a year old. The opposite is oligodactyly (fewer fingers or toes).
Treatment varies from removal by cautery to more involved surgery. While putting a tight band around the base has been carried out, this is not typically recommended. If surgery is required, this is often done around two years of age. Occasionally multiple surgeries are required.
Polydactyly is present in about 4 to 12 per 10,000 newborns. It is the most common defect of the hands and feet. In the United States, Black people are more commonly affected than White people. The term is from Greek πολύς (polys) 'many' and δάκτυλος (daktylos) 'finger'.
In humans/animals this condition can present itself on one or both hands or feet. The extra digit is usually a small piece of soft tissue that can be removed. Occasionally it contains bone without joints; rarely it may be a complete functioning digit. The extra digit is most common on the ulnar (little finger) side of the hand, less common on the radial (thumb) side, and very rarely within the middle three digits. These are respectively known as postaxial (little finger), preaxial (thumb), and central (ring, middle, index fingers) polydactyly. The extra digit is most commonly an abnormal fork in an existing digit, or it may rarely originate at the wrist as a normal digit does. Polydactyly can be divided into three major types, which are discussed below, which depend on the location of the additional digit.
In 2019 it was found that in cases of polydactyly with a fully functional additional digit, muscles to control the extra digit may be duplicated, resulting in increased motor control that allows the patient to carry out certain tasks with one hand that would normally require two.
This is the most common situation, in which the extra digit is on the ulnar side of the hand, thus the side of the little finger. This can also be called postaxial polydactyly. It can manifest itself very subtly, for instance only as a nubbin on the ulnar side of the little finger, or very distinctly, as a fully developed finger. Most commonly, the extra finger is rudimentary, consisting of an end phalanx with a nail, and connected to the hand with a small skin pedicle. Mostly one neurovascular bundle can be identified, with no tendons present in the extra digit. In case of a fully developed extra finger, the duplication usually presents itself at the level of the metacarpophalangeal joint. A triplication of the little finger is very rare. Ulnar polydactyly occurs ten times more often in African populations. The incidence in Caucasians is reported as 1 in 1,339 live births, compared with 1 in 143 live births in Africans. Ulnar polydactyly is also often part of a syndrome. In patients with African ancestry ulnar polydactyly mostly occurs isolated, whereas the presentation in Caucasians is often associated with a syndrome, though in a retrospective review, only 4 of 37 cases of ulnar polydactyly in Caucasians were syndromic.
This is a less common situation, in which the affectation is on the side of the hand towards the thumb. Radial polydactyly refers to the presence of an extra digit (or extra digits) on the radial side of the hand. It is most frequent in Indian populations and it is the second most common congenital hand disorder. The incidence of radial polydactyly is reported as 1 in every 3,000 live births. The clinical features of radial polydactyly will depend upon the extent of duplication. Radial polydactyly varies from a barely visible radial skin tag to complete duplication. Thumb polydactyly varies from barely visible broadening of the distal phalanx to full duplication of the thumb including the first metacarpal. Radial polydactyly is frequently associated with several syndromes.