Trichonodosis (knotted hair) was readily found in 36 of 134 normal subjects with various lengths and types of scalp hair. Knotting is an intriguing entity of common occurrence in subjects with long, kinky hair and occasionally may, in some patients, contribute to hair loss or obscure breakage.
English DT, Jones HE. Trichonodosis. Arch Dermatol. 1973;107(1):77-79. doi:10.1001/archderm.1973.01620160049014