Volcanoes produce a wide variety of natural hazards that can kill people and destroy property. This simplified sketch shows a volcano typical of those found in the Western United States and Alaska, but many of these hazards also pose risks at other volcanoes, such as those in Hawaii. Some hazards, such as lahars and landslides, can occur even when a volcano is not erupting.
A sphincter is a ring of muscle which holds any kind of biological opening closed. Sphincters are an important part of almost any system in a body. They help to both regulate the exit, entrance and circulation of fluids, gasses, and solids.
Sphincteroplasty: the surgical reconstruction of a sphincter muscle. This usually refers to the procedure that can be done on the muscles of the anal sphincter that control bowel movements.With obstetric trauma during vaginal delivery of a baby, this sphincter can become damaged and result in incontinence of stool.ith rectal or anal sphincter repair, the ends of the two circular anal muscles that control bowel movements are cut and overlapped onto one another and then sewn into place, creating a complete circle of muscle.