What is lumbar triangles?

The lumbar triangles are two triangular-shaped regions present on either side of the lower back, also known as the lumbar area. These are formed by the back muscles, the gluteal muscles, and the iliac crest (the upper border of the hip bone).

There are two lumbar triangles – the superior lumbar triangle, also known as Grynfelt's triangle, and the inferior lumbar triangle, also known as Petit's triangle.

Grynfelt's triangle is located above the iliac crest, bounded by the posterior margin of the external oblique muscle, the anterior margin of the latissimus dorsi muscle, and the medial edge of the 12th rib. Clinically, this region is important as hernias may occur through this triangle.

Petit's triangle is located below the iliac crest, bounded by the posterior margin of the external oblique muscle, the anterior margin of the latissimus dorsi muscle, and the iliac crest. This region is an important surgical site for some procedures such as renal transplantation, because of the easy access to the iliac vessels and the retroperitoneal space.

In conclusion, the lumbar triangles are important landmarks of the lower back region, with both Grynfelt's and Petit's triangle having clinical and surgical significance.