The etymology of the Small Intestines
Medieval anatomists named the three parts of the small intestines.
The duodenum is the first portion of the small intestine. It is derived from the Latin word “duodeni” meaning” twelve each.” Duodenum was named by Greek physician Herophilus (c.335–280 B.C.E.) for its length, about equal to the breadth of 12 fingers (it is approximately 10 inches long.)
The jejunum, the second portion of the small intestine, is approximately 20 feet long. It was always found empty by early anatomists. Thus, they named it jejunum, derived from the Latin word “jējūnus,” meaning “fasting.”
The ileum is the last portion of the small intestine and is approximately 11 feet long. Its name is derived from the Greek word “eilein” meaning to roll, because of its peristaltic movements. It was first used at the beginning of the 7th Century.