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Exams and Signs

Historical Overview

  • The word syndactyly derives from the Greek words “syn,” together, and “daktylos,” finger.
  • The first documented cases of syndactyly and polydactyly were written by Oribasius, a Byzantine physician of the 4th century.1


  • Syndactyly is diagnosed primarily by observation. Simple syndactyly involves fusion of the skin or tissues of fingers, whereas complex syndactyly involves fusion of bone, musculotendinous and/or neurovascular structures.2 Complete syndactyly extends to the fingertips, whereas incomplete syndactyly does not.3
  • Goals of operative treatment include improved aesthetic appearance and independent function of the fingers.4


  • About 80% of cases of syndactyly are sporadic. Syndactyly can also be related to conditions such as Apert’s syndrome, Poland’s syndrome, congenital constriction bands, and ectodermal dysplasia.


  1. Obtain an accurate and complete patient history. Ask the parent or guardian how severely the syndactyly prevents the patient’s independent function of the fingers.3,4
  2. Check for insufficient amount of skin and lack of vascular supply to the affected fingers.
  3. Examine the involved joints, to determine if they are ankylosed, deviated, stiff, or unstable.
  4. Check the contralateral hand; about 50% of cases of syndactyly are bilateral.

Related Signs and Tests

  • Radiographs
  • Sonographic studies

Diagnostic Performance Characteristics

  • Using radiographs will improve the reliability of a physical diagnosis.

Differential Diagnoses

  • Apert’s syndrome
  • Symbrachydactyly
  • Brachysyndactyly
  • Pseudosyndactyly
  • Ectrodactyly
  • Constriction band syndrome

Presentation Photos and Related Diagrams
Clinical Photos of Syndactyly
  • Simple Syndactyly Left Long and Ring Fingers Dorsal view.
    Simple Syndactyly Left Long and Ring Fingers Dorsal view.
  • Simple Syndactyly Left Long and Ring Fingers palmar view.
    Simple Syndactyly Left Long and Ring Fingers palmar view.
Definition of Positive Result
  • A positive result occurs when the patient presents with fusion of the skin, tissues, bone, musculotendinous and/or neurovascular structures of fingers.
Definition of Negative Result
  • A negative result occurs when the patient does not present with fusion of the skin, tissues, bone, musculotendinous or neurovascular structures of fingers.
Comments and Pearls
  • A typical age for operative treatment of a patient with syndactyly would be 6-18 months.5
  • In treating syndactyly, it is important only to operate on one side of a finger at a time. This will help to prevent web creep. It is also advisable only to operate on one hand at a time, unless the patient is very young and might be at greater risk from anesthesia.3
  • Operative complications include infection, scarring and division of a nerve or tendon. After surgery, patients should be checked periodically until they reach skeletal maturity, because web creep and other complications can occur.5
Diagnoses Associated with Exams and Signs
  1. Papadakis M, Manios A, Trompoukis C. Surgical treatment of polydactyly and syndactyly during the 4th century AD. Acta Chir Belg2018:1-2. PMID: 30388389
  2. Rayan G, Akelman E. The Hand: Anatomy, Examination and Diagnosis. Philadelphia: Lippincott Williams & Wilkins, 2012
  3. Flatt AE. Webbed fingers.Proc (Bayl Univ Med Cent)2005;18(1):26-37. PMID: 16200145
  4. Kvernmo HD, Haugstvedt JR. Treatment of congenital syndactyly of the fingers. Tidsskr Nor Laegeforen2013;133(15):1591-5. PMID: 23970273
  5. Dao KD, Shin AY, Billings A, et al. Surgical treatment of congenital syndactyly. J Am Acad Orthop Surg2004;12(1):39-48. PMID: 14753796
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