According to WebMD, a split tongue is usually not a cause for alarm. It is also called a fissured tongue and often has a benign cause. However, it sometimes indicates an underlying medical condition, such as geographic tongue, Down syndrome or Melkersson-Rosenthal syndrome.
WebMD explains that in some cases, a split tongue is often a harmless, inherited trait. Geographic tongue, or benign migratory glossitis, is a condition that causes tongue discoloration and sometimes splitting. The condition usually heals without treatment.
WebMD characterizes Down syndrome as a genetic birth defect with distinct physical characteristics and mental limitations. Melkersson-Rosenthal syndrome is a rare condition that, in addition to the fissured tongue, causes lip and intermittent facial paralysis. The National Institutes of Health also list a deep, hard-edged crack on the tongue as an indication of oral cancer.
The usual characteristics of fissured tongues include clefts, grooves or cracks along the sides and top of the tongue. While they vary in length, some may be as deep as six millimeters, according to WebMD. Sometimes the splits connect with other splits along the tongue, which causes the tongue to separate into two or more sections. Most individuals who are afflicted with this condition do not experience any symptoms until some type of debris gets lodged into the split and causes discomfort. Dentists often find splits in the tongue upon routine oral examinations.