| Lumbar triangle | |
|---|---|
 The superior and inferior lumbar triangles with a cross section at the level of the superior lumbar triangle | |
 Posterior view of muscles connecting the upper extremity to the vertebral column. Lumbar triangle is labeled in red at bottom left. | |
| Details | |
| Identifiers | |
| Latin | trigonum lumbale |
| TA98 | A01.2.05.009 |
| TA2 | 270 |
| FMA | 75023 |
| Anatomical terminology | |
Thelumbar triangle can refer to either the inferior lumbar (Petit) triangle, which lies superficially, or the superior lumbar (Grynfeltt) triangle,[1] which is deep and superior to the inferior triangle. Of the two, the superior triangle is the more consistently found incadavers[2] and is more commonly the site ofherniation; however, the inferior lumbar triangle is often simply called the lumbar triangle, perhaps owing to its more superficial location and ease in demonstration.
The margins of the inferior lumbar (Petit's) triangle are composed of theiliac crest inferiorly and the margins of two muscles –latissimus dorsi (posteriorly) andexternal abdominal oblique (anteriorly). The floor of the inferior lumbar triangle is theinternal abdominal oblique muscle. The fact that herniations occasionally occur here is of clinical importance.[3] A lumbar hernia here is called aPetit's hernia.
The superior lumbar (Grynfeltt-Lesshaft) triangle is formed medially by thequadratus lumborum, laterally by theposterior border of internal abdominal oblique muscle, and superiorly by the 12th rib. The floor of the superior lumbar triangle is thetransversalis fascia and its roof is the external abdominal oblique muscle. AGrynfeltt-Lesshaft hernia can occur here.
