Syndactyly (plural: syndactylies) refers to a congenital fusion of two or more digits. It may be confined to soft tissue (soft tissue syndactyly/simple syndactyly) or may involve bone (bony syndactyly/complex syndactyly).
The overall estimated incidence is at ~1 per 2,500 to 5,000 live births 6,8. There may be a greater male predilection.
Syndactyly can occur as an isolated phenomenon or can be associated with numerous other entities. Isolated cases can be either sporadic or familial.
- triploidy: tend to affect the 3rd and 4th digits of the hands
- amniotic band syndrome 3
- Fraser syndrome / cryptophthalmos syndrome 4
- Gorlin syndrome
- Greig cephalopolysyndactyly syndrome 5
- macrodystrophia lipomatosa
- Pallister-Hall syndrome
- Poland syndrome
- proximal radioulnar synostoses: Cenani Lenz syndactyly
- prune belly syndrome
- Roberts syndrome
- VACTERL association
- Down syndrome 10
- neurofibromatosis type 1 11
- isolated polydactyly, a.k.a. polysyndactyly
- isolated brachydactyly, a.k.a. brachysyndactyly
- isolated ectrodactyly
There is a very wide spectrum of syndactyly ranging from partial to complete.
Overall, the 2nd and 3rd digits tend to be most frequently associated 6. May involve the toes more than fingers.
Postnatally the type and degree of bony syndactyly can be easily diagnosed on plain film.
Often difficult to diagnose on ultrasound (especially with soft tissue syndactyly). The diagnosis may be suggested if the digits appear to constantly move together 7. The fingers may appear constantly deformed with complex syndactyly 6.
Treatment and prognosis
The overall prognosis can be extremely variable depending on the presence of other associated anomalies.
History and etymology
The term syndactyly is derived from the Greek words 'syn' meaning together and 'daktulos' meaning fingers.
- 1. Grünebaum M. Pediatric Radiological Signs. iUniverse. (2005) ISBN:0595339603. Read it at Google Books - Find it at Amazon
- 2. Chew FS, Chew FS. Skeletal Radiology, The Bare Bones. Lippincott Williams & Wilkins. (2010) ISBN:1608317064. Read it at Google Books - Find it at Amazon
- 3. Entezami M, Albig M, Knoll U et-al. Ultrasound Diagnosis of Fetal Anomalies. Thieme. (2003) ISBN:1588902129. Read it at Google Books - Find it at Amazon
- 4. Levine RS, Powers T, Rosenberg HK et-al. The cryptophthalmos syndrome. AJR Am J Roentgenol. 1984;143 (2): 375-6. AJR Am J Roentgenol (citation) - Pubmed citation
- 5. Timor-tritsch IE, Kapp S, Berg R et-al. Greig cephalopolysyndactyly syndrome: diagnosis based on prenatal sonographic features coupled with comparative genomic hybridization. J Ultrasound Med. 2009;28 (12): 1735-42. J Ultrasound Med (full text) - Pubmed citation
- 6. Rypens F, Dubois J, Garel L et-al. Obstetric US: watch the fetal hands. Radiographics. 26 (3): 811-29. doi:10.1148/rg.263055113 - Pubmed citation
- 7. Ryu JK, Cho JY, Choi JS. Prenatal sonographic diagnosis of focal musculoskeletal anomalies. Korean J Radiol. 4 (4): 243-51. Korean J Radiol (link) - Free text at pubmed - Pubmed citation
- 8. Yochum TR, Rowe LJ. Essentials of skeletal radiology. Lippincott Williams & Wilkins. (2005) ISBN:0781739462. Read it at Google Books - Find it at Amazon
- 9. Chong AK. Common congenital hand conditions. Singapore Med J. 2010;51 (12): 965-71. Singapore Med J (link) - Pubmed citation
- 10. Conen PE, Hampole MK, Thomson HG. Chromosome abnormalities in patients with syndactyly. (1969) Canadian Medical Association journal. 101 (10): 75-8. Pubmed
- 11. Wolfgang Dähnert. Radiology Review Manual. (2011) ISBN: 9781609139438