|Classification and external resources|
The picture above illustrates a moderately severe case of this condition.
Clinodactyly (from the Ancient Greek klinen meaning "to bend" and daktylos meaning "digit") is a medical term describing the curvature of a digit (a finger or toe) in the plane of the palm, most commonly the fifth finger (the "little finger") towards the adjacent fourth finger (the "ring finger").
Clinodactyly is an autosomal dominant trait that has variable expressiveness and incomplete penetrance.
Clinodactyly can be passed through inheritance and presents as either an isolated anomaly or a component manifestation of a genetic syndrome. Many syndromes are associated with clinodactyly, including Down Syndrome, Aarskog syndrome, Carpenter syndrome, Seckel syndrome, Cornelia de Lange syndrome, Orofaciodigital syndrome 1, and Silver–Russell syndrome.
When identified prenatally, for example during obstetric ultrasonography, it may be an indication for intrauterine sampling for foetal chromosome analysis as it is statistically correlated with increased risk of chromosome aberration in the fetus.
Due to a developmental arrest there is an abnormal alignment of the joint surfaces at either interphalangeal joint causing angulation in the plane of the palm. The finger may be slightly bent or have a very prominent bend.
There is no consensus on what degree of angulation justifies a diagnosis, an incline between 15° and 30° is typical. 
Not to be confused with Camptodactyly which is a fixed flexion deformity of a digit.
Treatment is only necessary if the degree of curvature is sufficient to cause disability or if it causes emotional distress.
Splinting does not routinely correct the deformity. Surgical treatments are closing wedge osteotomy, opening wedge osteotomy, and reversed wedge osteotomy. Radiographs of the fingers are useful in planning the surgical procedure. Severe clinodactyly may require soft tissue alterations to the digit such as release of skin, extensor tendon relocation, and collateral ligament advancement. 
Minor degrees of curvature are common.
Reports of incidence vary between 1% and 19.5%.
- Flatt, Adrian E (October 2005). "The troubles with pinkies". Baylor University Medical Center Proceedings 18 (4): 341 to 344. PMC 1255945. Retrieved 16 September 2014.
- Leung, Alexander K C; Kao, C Pion (December 2003). "Familial clinodactyly of the fifth finger". Journal of the National Medical Association 95 (12). PMC 2594860. Retrieved 16 September 2014.
- Hersh, A. H.; DeMarinis, F.; Stecher, Robert M. (September 1953). "On the inheritance and development of clinodactyly". The American Journal of Human Genetics 5 (3): 257 to 268. PMC 1716475. Retrieved 16 September 2014.