Which cavity begins at the level of the iliac crest?

The pelvic cavity begins at the level of the iliac crest because this anatomical landmark is located at the upper edge of the pelvis. The iliac crests are part of the hip bones, and they mark the division between the abdominal cavity, which is located above, and the pelvic cavity, which sits below. Understanding this distinction is vital in medical terminology as it underscores the organization and relationship of the body’s internal spaces.

The abdominal cavity is situated above the iliac crests, extending from the diaphragm down to the area where it meets the pelvic cavity. The mediastinum is located in the thoracic cavity, which is found within the chest and contains vital organs such as the heart and lungs, but does not extend to the iliac crest. The thoracic cavity is distinctly separate from both the abdominal and pelvic cavities. Thus, recognizing that the iliac crest marks the transition from the abdominal cavity to the pelvic cavity is essential for proper anatomical orientation.