A bone anchor includes a shaft having a first end and a second end, a bore extending from the first end to the second end, and a plug member which is insertable into the bore and guidable through the bore for closing the bore at the second end. The bone anchor is suitable for minimally invasive surgery in such a way a guide wire can be guided through the bone anchor and after the bone anchor has been anchored in the bone the plug member is inserted to close the open end of the bone anchor. A bone cement or a pharmaceutical substance can be introduced into the bone anchor.