Table 1.

Formation of Pilonidal Sinus

• A midline pit develops that may be a hair follicle, which has shed its own hair and then allows debris to occupy the pit.

• Loose semicurved roots of hair fall and migrate to the cleft where they become vertically oriented and insert into the pit via their roots.

• A foreign body granuloma develops in the subcutaneous fat.

• The depth of the natal cleft is associated with anaerobic environment with moisture and pressure that can lead to increased hair insertion.

• The direction of the follicle determines the direction of the tract.