In a human body the coccyx bone is at cleave of the buttocks and the cyst that develops along this tail bone is known as Pilonidal Cyst. Some of these cysts do not have any symptoms at all and some are associated with inflammation and pain. Diffusion of loose hairs into the skin is the main cause of this disease. The cyst is formed around this ingrown hair and this infection increases if there is excessive pressure or strain in that region specifically. There is history of hereditary cysts but that is very rare. Person who is in occupation of sitting most of the time, and highly obese people tend to suffer from this disease the most.