Lumbar triangle

The lumbar triangle can refer to either the inferior lumbar (Petit) triangle, which lies superficially, or the superior lumbar (Grynfeltt) triangle, which is deep and superior to the inferior triangle. Of the two, the superior triangle is the more consistently found in cadavers and is more commonly the site of herniation; however, the inferior lumbar triangle is often simply called the lumbar triangle, perhaps owing to its more superficial location and ease in demonstration.

Inferior lumbar (Petit) triangle

The margins of the inferior lumbar (Petit's) triangle are composed of the iliac crest inferiorly and the margins of two muscles – latissimus dorsi (posteriorly) and external abdominal oblique (anteriorly). The floor of the inferior lumbar triangle is the internal abdominal oblique muscle. The fact that herniations occasionally occur here is of clinical importance. A lumbar hernia here is called a Petit's hernia.

Superior lumbar (Grynfeltt-Lesshaft) triangle

The superior lumbar (Grynfeltt-Lesshaft) triangle is formed medially by the quadratus lumborum, laterally by the posterior border of internal abdominal oblique muscle, and superiorly by the 12th rib. The floor of the superior lumbar triangle is the transversalis fascia and its roof is the external abdominal oblique muscle. A Grynfeltt-Lesshaft hernia can occur here.

References

External links

• Anatomy photo:01:02-0104 at the SUNY Downstate Medical Center

1. Hernia
2. Latissimus dorsi muscle
3. Grynfeltt–Lesshaft hernia
4. Lumbar plexus
5. Erector spinae muscles
6. Petit's hernia
7. Appendicitis
8. Abdominal external oblique muscle
9. Abdominal internal oblique muscle
10. Serratus posterior inferior muscle
11. Petit
12. Lumbocostal triangle
13. Vertebra
14. Sacrum
15. Transverse abdominis plane block
16. Femoral nerve
17. Iliopsoas
18. Triangle of Doom
19. Pectineus muscle
20. Groin