Syndactyly: Definition, Causes, Forms, Symptoms, Diagnosis, Treatment and Prediction

It is a genetic disorder in which a child is born with the fingers of the hands or feet joined together.

Syndactyly is one of the most common birth defects and most often occurs between families.

This condition is more common in boys than in girls. Syndactyly usually affects both hands at the same time and is seen to occur between the middle and ring fingers.

This condition does not have a remarkable cause and can occur in isolation or is inherited. Syndactyly may also occur in association with other genetic disorders such as the Apert syndrome or the Poland syndrome.

Syndactyly can be detected prenatally if there is a family history of this condition when performing an ultrasound.

It is mainly treated with surgery, but the exact course of treatment is formulated by the doctor after performing radiological studies and performing other studies on the child. The surgery must be done when the child is one year old to obtain optimal results.


Syndactyly is a fairly common condition and is present in approximately 20% of children born with just one hand. Studies suggest that Caucasians are more likely to have syndactyly than others.

Although the main cause of syndactyly is unknown, studies suggest that during the sixth or seventh week of pregnancy when the fingers are separated there is some kind of abnormality that causes the fingers not to separate and fuse or clap together.

Syndactyly forms

According to studies, syndactyly has been classified into four forms, the first of which is the complete form in which the straps extend to the tips of the fingers. Then there is the incomplete form in which the tape does not cover the entire finger.

The third form is the simple form of syndactyly in which the fingers are joined by a flap of skin or soft tissue and then there is the complex form of syndactyly in which there is presence of bone and cartilage together with soft tissue in the straps.

Then the most severe or complicated form of syndactyly in which the fingers are joined by bone, cartilage, tendons and soft tissues that are the most difficult to treat.


Syndactyly is a defect that is quite visible at birth, although it can be detected prenatally by ultrasound. This is especially useful for those parents who have a family history of this condition.

¿Cómo if you diagnose sindactilia?

As stated, syndactyly is a visible deformity and can be easily visualized at birth. Once the network is observed, the doctor will perform detailed radiological studies in the form of X-rays or MRI to observe the internal structures of the affected fingers in order to formulate a treatment plan and the best way to treat the child.


The best way to treat children with syndactyly is to release the strap that joins two fingers. This is easier if the fingers are webbed or joined by a simple flap of soft tissue without bones or cartilage.

The procedure is performed when the child is one year of age to obtain the best results. Surgical treatment of syndactyly is known as Z-plasty, in which the skin is divided incidentally in the form of letter Z.

In a moment, only one side of the finger is separated to avoid complications after surgery. In some cases, more than one procedure may be necessary to obtain better results.

Rarely, there are complications related to surgery for syndactyly, but some of the complications include:

  • Insufficient blood supply to the affected finger.
  • Scar contractions.
  • Deformity of the nail plate.

What is the prognosis of syndactyly?

Fortunately, the overall prognosis for syndactyly is quite good, and most children have normal hand function when they grow up.

A minimal deformity is also observed in the fingers that have been divided and, therefore, the appearance is also almost normal.

The child will need a thorough follow-up for a few months to make sure that the healing process is adequate, the function is normal on the affected finger with an adequate supply of blood and to see if additional surgery is required for the correction.