The intertubercular plane (also called the transtubercular plane or plane of Ludwig) is a transverse anatomical landmark used in the surface anatomy of the human abdomen. It is defined as a horizontal line that passes through the tubercles of the iliac crests on both sides of the pelvis.
Location
- The plane lies approximately at the level of the upper border of the fifth lumbar vertebra (L5).
- It is situated midway between the upper transverse (subcostal) plane and the upper border of the pubic symphysis.
Anatomical significance
- The intertubercular plane divides the abdomen into inferior and superior regions and is employed in the nine‑region abdominal division.
- It serves as a reference point for locating underlying viscera, such as the lower portions of the kidneys and portions of the large intestine, and for guiding clinical examinations and imaging.
Clinical and educational usage
- In physical examination, the plane helps clinicians approximate the level of abdominal structures without imaging.
- In radiology and surgery, it provides a reproducible external reference for planning incisions or interpreting cross‑sectional images.
Etymology
- The term derives from “inter‑” (between) and “tubercular,” referring to the iliac tubercles—prominent bony points on the iliac crests.
References
- Wikipedia, “Intertubercular plane,” which cites Gray’s Anatomy (20th edition, 1918).
- e‑Anatomy (IMAIOS) and other anatomical textbooks describe the plane as the horizontal line connecting the iliac tubercles at the L5 vertebral level.