Congenital syndactyly is the congenital pathological connection of 2 or more fingers and their related tissue components, and is one of the most common types of hand deformities. The incidence is 1:2000 to 1:2500; the incidence is higher in males than in females, accounting for 56% to 84%; the incidence is 10 times higher in Caucasians than in Blacks, and 10% to 40% have a family history of inheritance, usually autosomal dominant. In the separate parallel fingers, the middle ring finger is most likely to be involved, 57%, followed by the ring pinky finger for 27%, the thumb and middle finger are less involved, but in the malformation syndrome, the thumb and middle finger are relatively more involved. In the fourth week of embryonic development, the lateral body wall of the embryo forms and starts mitosis, and the upper limb bud appears and grows gradually; in the fourth and fifth week, the ectodermal parietal ridge is formed, and the distal hand plate appears, with traces of finger plates on the margins; in the fifth week, the mesodermal cells in the finger plate, which are radially agglomerated, differentiate to form finger lines. The finger line is separated by the finger web tissue; at week 6, the radial apoptotic zone between the finger webs first forms dorsally, then the finger tips separate, and the apoptotic process between the finger webs gradually extends proximally, and the finger web gap forms by the end of week 6, but the fingers continue to lengthen and form a tactile pad at the end of the fingers, and the finger bones are in a state of gradual differentiation; at week 8, the center of metacarpal ossification appears, and finger independence is nearly At week 8, the metacarpal phalangeal bone is complete and the finger independence is almost complete; at week 11, the finger separation is complete and the ossification centers of all phalanges appear. Clinical classification For the purpose of treatment selection and prognosis assessment, there are two main clinical categories of syndactyly, simple and complex syndactyly, depending on the tissues involved. Simple syndactyly is divided into complete and incomplete syndactyly according to the extent of the skin connection of the finger web. However, since the occurrence of syndactyly is due to the impaired differentiation of the adjacent fingers, syndactyly may involve the whole hand or some of the fingers, and even simple syndactyly may be complex (e.g., a deformity of the bone combined with a short finger deformity); syndactyly may be an independent disorder or a specific manifestation of other syndromes (e.g., acral syndactyly, hand hypoplasia, flexor digit deformity, Apert syndrome, Poland syndrome, etc.). Poland syndrome, etc.). Complicated syndactyly is not strictly limited to its own classification like other malformations (independent syndactyly is classified as type II congenital malformation), but is widely distributed among other malformations, most often involving the middle ring finger if it is an independent disorder, and 10%-40% of patients have a family history of the disease. Complex syndactyly involves not only bone and skin, but may also involve the musculotendinous system and neurological structures. The more complex the deformity, the closer the common finger artery bifurcation will be to the distal end, while the other vessels of the finger may not develop. Timing of surgery The timing of surgery is related to the complexity of the syndactyly and the fingers involved and is individualized, but because the cortical innervation area of the fingers for grasping function is already formed at 2 years of age, most scholars still recommend 2 years as the upper age limit, usually done between 12-24 months after birth. Bilateral deformities should be completed before the child can walk, if possible. In infancy and early childhood, surgery is generally inappropriate because of the short fingers, the difficulty in designing flaps and skin grafts, and the difficulty in fixing them after surgery. Children grow and develop quickly, so if surgery is performed too early, the postoperative scar will not be able to catch up with the development of the hand, and contracture may occur gradually, which often needs to be repaired by surgery. If the juxtaposed fingers are not at the same joint level and the fingers affect each other’s flexion and extension activities, the surgery should be done early to avoid affecting the development. In the case of multiple finger syndactyly, the surgery should be performed in stages to avoid ischemic necrosis of the middle finger. Once the syndactyly is detected, the child can be given appropriate split-finger massage activities to facilitate the expansion of the skin between the syndactyly. Syndactyly may coexist with other organ malformations, so a thorough physical examination should be done after detection. Some photos of the syndactyly are attached