Abomasum

**Definition:** The fourth stomach of ruminating animals. It is also called the true stomach. It is an elongated pear-shaped sac lying on the floor of the abdomen, on the right-hand side, and roughly between the seventh and twelfth ribs. It leads to the beginning of the small intestine. (From Black's Veterinary Dictionary, 17th ed)

**Tree numbers:** - A13.869.106