You may also have diarrhea or a fever. It is sometimes called stomach flu, but it is not the flu. Germs like viruses and bacteria can cause it. You can catch it from someone else who has it, or you can get it from food poisoning. Food poisoning can happen if you eat foods that contain harmful germs.
The circular muscle located at the entrance and exit to the stomach is called the sphincter. So for this question, you are talking about two distinct sphincters. This anatomical structure is able to open, and contract or close as needed.
The External Oblique Muscle (pp. 132-3). 1  This is the largest and most superficial of the three flat abdominal muscles. 2  It is located in the anterolateral aspect of the abdominal wall. 3  Its fleshy part forms the anterolateral portion and its aponeurosis forms the anterior part.osterior Abdominal Wall. 1  The posterior abdominal wall is composed principally of muscles and fascia attached to the vertebrae, hip bones, and ribs. 2  It also contains fat, important nerves, vessels, and lymph nodes.