Persistent constriction of the foreskin, which does not allow to fully expose the head of the penis. It can be congenital and acquired, for example, due to cicatricial changes in the foreskin with chronic balanoposthitis.
In newborns phimosis is a physiological phenomenon. By the age of 2-3 years, loose adhesions between, the head of the penis and the foreskin are destroyed and its ring expands. Violation of this process leads to phimosis. Forced exposure of the head can lead to its infringement by the ring of the foreskin (paraphimosis). Treatment of phimosis is only surgical - excised foreskin.