Lumbosacral trunk

The lumbosacral trunk is the distal trunk of the lumbar plexus arising from the anterior rami of the L4 and L5 nerve roots which contributes to the sacral plexus.

Gross anatomy


It arises from anterior rami of L4-L5 roots of the lumbar plexus.

  • emerges over the medial border of the iliacus muscle, medial to the psoas major muscle
  • it descends to join with the S1 nerve root to contribute to the sacral plexus

The lumbosacral trunk contributes fibres to the:

Anatomy: abdominopelvic
Share article

Article information

rID: 38798
Section: Anatomy
Synonyms or Alternate Spellings:

Support Radiopaedia and see fewer ads

Cases and figures

  • Drag
    Figure 1: lumbosacral trunk
    Drag here to reorder.
  • Drag
    Figure 2: lumbar plexus labelled
    Drag here to reorder.
  • Updating… Please wait.

    Alert accept

    Error Unable to process the form. Check for errors and try again.

    Alert accept Thank you for updating your details.