Polydactyly describes the existence of more than five fingers on one hand or more than five toes on one foot. Due to an autosomal dominant inheritance, the affected person inherits this deformity from one parent. Polydactyly exists in different classifications and manifestations.


What is polydactyly?

The term polydactyly is used medically to describe extra fingers or toes in the upper or lower extremities. The anomaly is present at birth and is therefore a congenital disease. This is caused by increased longitudinal segmentation during the embryonic phase. The extra toes and fingers can be different. See polyhobbies for Meanings of Persistierender Ductus Arteriosus.

Shape and size as well as location can vary enormously. These can be very small and non-functional and only exist as flaps of skin. A large addition usually has a complete bone structure and skeletal connections. Polydactyly occurs very frequently on both sides and mostly in the upper extremities. An abnormality in just one foot or hand is less common, but is also possible. The classification can be done by localization.

On the hand side, a distinction is made between radial, ulnar and central:

  • Radial when the extra finger is next to that of the thumb. So in this case it is a thumb doubling.
  • Ulnar if present next to the little finger.
  • Centrally between the second to fourth fingers.

Polydactyly can occur in both humans and animals.


In most cases, the cause of polydactyly is autosomal dominant inheritance. Various mutations can be inherited by the child and manipulate the control of a gene’s expression. The variety of mutations is responsible for the different localizations and forms. During embryonic development in the mother’s womb, the hands of the embryo initially have the shape of a paddle. Only after the sixth week of pregnancy does the surface of the paddle split into separate fingers.

This process is possible with the help of apoptosis, the programmed death of body cells. The unnecessary cells between the fingers are thus driven to self-destruction. Irregularities during this phase can form polydactyly. This anatomical abnormality occurs when one finger is split into two. Older maternal age or increased testosterone levels during pregnancy increase the risk.

Alternatively, polydactyly can be one of the many accompanying symptoms of various syndromes. This is often observed in Ellis-van-Crevelt syndrome, Bardet-Biedl syndrome, Carpenter syndrome and Down syndrome. And with trisomy 13 and 18.

Symptoms, Ailments & Signs

Since toes or fingers abound in polydactyly, the foot or hand is common. A wide forefoot can be problematic when purchasing footwear. Difficulties in locomotion and maintaining body balance may also arise. This can eventually lead to back and hip problems.

Additional structures can create spatial constraints and axis deviations in the footwell. Centrally located polydactyls are particularly affected by this problem. If there is not enough space between the adjacent toes and fingers, imprints and excessive sweating can occur. Possible consequences on the feet are corns, fungal infections, calluses, blisters and an unpleasant smell of foot sweat.

If the additional structure is particularly large and affects the entire tissue, it can form severe bone deformations. Such as hallux varus or hallux valgus. In addition, sufferers complain of aesthetic complaints. Polydactyly is extremely conspicuous and appears strange. The deformity can also be extremely pronounced.

Diagnosis & course of disease

If the foot or hand is affected by gigantism, polydactyly can be easily identified with the naked eye. In this case, the clinical findings are very clear. Minimal formations, height and shape can be diagnosed using an x-ray. With sonography, polydactyly can be identified as early as the fourteenth week of pregnancy.


Those affected by polydactyly suffer from extra fingers or extra toes on their feet. As a rule, polydactyly does not pose any particular health risk, so that the patient’s life expectancy is usually not negatively affected by the disease. However, there can be various complaints and limitations in the patient’s everyday life, so that usual activities can sometimes no longer be carried out easily.

In addition to the extra fingers or toes, the patients also suffer from hip or back problems. This can also lead to restrictions in movement. Polydactyly also leads to excessive sweat production and further unpleasant odors or fungal infections. The patient’s quality of life is therefore significantly reduced by this disease.

Without treatment, deformations of the bones also occur, which are usually associated with pain. The extra toes or fingers can be removed through surgery. There are no complications. Other symptoms can also be limited and alleviated with various therapies.

When should you go to the doctor?

Polydactyly should always be evaluated by a doctor. This disease does not heal itself. The symptoms significantly restrict the life of the person affected, so that treatment can significantly improve the quality of life. A doctor should be consulted for this condition if the person affected has an excessive number of toes or fingers. The extra toes or fingers can appear on both limbs or just one limb and make life more difficult.

The doctor should also be consulted for this disease if polydactyly leads to excessive sweating or if blisters and corns form on the limbs. A psychologist can also be consulted in the case of psychological complaints due to the limited aesthetics, since bullying and teasing can occur, especially in children. Polydactyly can be diagnosed by a general practitioner or a pediatrician. Further treatment is then usually surgical without complications. The patient’s life expectancy is also not negatively affected by this disease.

Treatment & Therapy

Surgical treatment can be performed to improve aesthetics and function. The extra fingers and toe are thus removed. Many other corrections are required and ensure the comfort and usability of the hand or foot. Movable skin appendages are usually tied off shortly after birth and fall off. In the case of a thumb doubling, operations from the eighth month of life are optimally suited.

However, restricted mobility and instability of the joints often follow. In some cases, a nail deformity develops. The outcome often depends on the severity of the anomaly. The greater the deformity, the more likely it is that correction will be necessary. Central polydactyly is treated surgically in the first or second year of life. This will prevent contracture and deviation. A postoperative unfavorable vascular distribution can lead to circulatory disorders with subsequent necrosis.

The result is usually very bad with many subsequent corrections. If the parents of the affected child decide against surgical treatment, the appropriate footwear must be made orthopedically from the beginning of the walking age. The foot must have enough space to counteract skin diseases and other bone deformities. Special shoe inserts will most likely be required as well.


Since polydactyly is an autosomal dominant hereditary disease, there are no preventive measures. If one parent is affected by this anatomical anomaly, the offspring has a 50 percent chance of inheriting it as well. However, the structure can be determined from the fourteenth week of pregnancy using a sonography.


In most cases, sufferers of polydactyly have no special or direct follow-up measures available. Ideally, those affected should consult a doctor at an early stage so that there are no further complications or restrictions in everyday life. The disease itself does not always have to be treated.

In most cases, patients are dependent on a surgical procedure, which can alleviate the symptoms. The person concerned should definitely rest after such an operation and protect his body. Here, exertion or other stressful and physical activities should be avoided in order not to unnecessarily burden the body.

If polydactyly occurs on the feet, special shoes and insoles can also be used to counteract the symptoms. Regular check-ups and examinations by a doctor are also very important. In children, parents should recognize the signs and symptoms of polydactyly early and then consult a doctor. Further follow-up measures are usually not available to the patient and are also not necessary.

You can do that yourself

Polydactyly does not necessarily require medical treatment. The most important self-help measure is not to subject the affected limb to any further stress. This can be achieved, for example, by wearing a special bandage that fixes the excess limbs.

After an operation, the affected hand should initially be rested. Physiotherapy and physiotherapy support recovery by optimizing the mobility of the other fingers. Polydactyly is not a serious condition and therefore does not require any further measures. After the superfluous limbs have been surgically removed, the majority of patients are symptom-free. However, the affected hand or foot should be observed. If inflammation develops or other unusual symptoms appear, the doctor must be informed.

If the optical flaw has a negative effect on the mental state, the doctor must be informed. A psychological discussion with a therapist is usually sufficient to overcome the insecurity. Severe polydactyly, where there are seven or more fingers or toes on one hand or foot, may require additional medical attention. The patient should contact the responsible orthopedist and talk to them about suitable self-help measures such as movement exercises or muscle relaxation.