What is the Difference Between Ilium and Ileum?

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The terms "ilium" and "ileum" are often confused due to their similar spelling and pronunciation. However, they refer to different structures in the human body:

  • Ileum: This is the final segment of the small intestine in most vertebrates. It lies between the jejunum and the cecum, and its main role is to absorb bile salts, vitamin B12, and other digestive products that the jejunum did not absorb.
  • Ilium: This is the uppermost portion of the hip bone in a majority of vertebrates, including humans. In humans, the ilium is composed of two parts: the wing and the body. The ilium, along with the ischium and pubis, forms the pelvic girdle, providing structural support and performing weight-bearing functions.

To remember the difference between the two terms, you can use the following mnemonics:

  1. Both "ilium" and "hip" have an "-i-" in the middle.
  2. "Ileus" affects the "ileum," and both words have an "-e".
  3. The two "-i-" in "ilium" resemble bones, while the "-e" in "ileum" is squiggly like an intestine.

By keeping these distinctions in mind, you can avoid confusion when discussing the ileum and ilium.

Comparative Table: Ilium vs Ileum

Here is a table highlighting the differences between the ileum and ilium:

Feature Ileum Ilium
Definition The ileum is the final segment of the small intestine in most vertebrates, responsible for absorbing bile salts, vitamin B12, and other digestive products. The ilium is the uppermost portion of the hip bone in most vertebrates, part of the pelvic bone structure, and serves as a site for muscle attachment.
Location The ileum is located between the jejunum and the cecum of the large intestine. The ilium is found in the pelvic region of the body, forming the upper boundary of the pelvic bones.
Structure The ileum is a soft muscular structure and measures about 1.8 meters (6 feet) in length. It is thicker, more vascular, and has more developed mucosal folds than the jejunum. The ilium is a part of the hip bone and is composed of two parts, namely the wing and the body. It forms the pelvic bone structure together with the ischium and pubis.
Function The ileum plays a crucial role in absorbing bile salts, vitamin B12, and other digestive products that were left unabsorbed by the jejunum. The ilium serves as a site for muscle attachment and provides structural support for the pelvic region.
In Vertebrates The ileum is found in most higher vertebrates, including reptiles, birds, and mammals. The ilium is found in humans, most birds, reptiles, and mammals, but is not present in bony fishes and snakes (although some snakes have similar bone structures).