A congenitally deformed toe–usually the fourth or fifth–which lies under the plane formed by the other toes and, by pushing on the other toes, causes irritation.
Differential diagnosis Underlapping may also be caused by mechanical stress and improper footwear, especially in a background of osteoarthritis and rheumatoid arthritis.
Management Simple corrective positional taping of underlapping (or overlapping) toes during the neonatal period corrects 94% of cases; after infancy, corrective shoes; if symptomatic, de-rotation arthroplasty
Synonyms Clinodactyly, curly toe
Reference Paediatr Child Health. 2007 November; 12(9): 755–759 acfas.org/brdigdis.html