A small depression with hairs at the base of the spine.
A hairy bump in the cleft of the buttocks in tissue near the tailbone; also known as a pilonidal cyst. A pilonidal sinus can become infected and form a painful abscess (pus-filled sac). Treatment is with antibiotics and, as necessary, either surgical incision and drainage or surgical excision (cutting out the cyst).
A short tract leading from an opening in the skin in or near the cleft at the top of the buttocks and containing hairs. The sinus may be recurrently infected, leading to pain and the discharge of pus. Treatment is by surgical opening and draining of the infected sinus, which is later excised.
A skin indentation, frequently housing hairs, situated in the upper region of the buttock crease. The likely cause is the inward growth of hair fragments. While this condition is generally benign, there is a possibility of infection, leading to the recurrence of painful abscesses.
In cases of infection in a pilonidal sinus, a surgical procedure involves the removal of the sinus itself along with a substantial surrounding area. Typically, the resulting wound is intentionally left open to facilitate gradual healing from the underlying skin layers. Reoccurrence of infection is frequently observed, and in certain instances, plastic surgery may become necessary.