Abdominal regions

The transtubercular plane (also called the transtubercular line) is one of the surface reference lines used in surface anatomy to delineate the abdominal regions.

It is a horizontal or transverse plane that passes through the iliac tubercles, small elevations found in the iliac crest of the iliac bone. These tubercles can be palpated in a thin person, but their location can be approximated if you take the distance between the transpyloric plane and the superior aspect of the pubic symphysis and divide it in half.

The transtubercular plane marks the location of the body of the fifth lumbar vertebra and the location of the confluence of both common iliac veins to form the inferior vena cava.

Sources:
1. "Clinical Anatomy" Brantigan, OC 1963 McGraw Hill
2. "Tratado de Anatomia Humana" Testut et Latarjet 8th Ed. 1931 Salvat Editores, Spain
3. Davis, Gwilym G. "Applied Anatomy: The Construction of the Human Body Considered in Relation to Its Functions, Diseases, and Injuries"; Philadelphia: J.B. Lippincott Co., 1910
Image modified from the original Davis, 1910