Skip to Main Content

++

  • The lumbar plexus is usually formed by the ventral rami of the L1–L3 and part of the ventral branch of L4
  • The sacral plexus is formed by the lumbosacral trunk (L4, L5), the first sacral ventral ramus, part of the ventral branch of S2, and a small portion of the ventral branch of S3
  • Classically, the ventral branch of L4 is the junction between the two plexi; it gives off a branch to the femoral nerve, one to the obturator nerve, and the lumbosacral trunk that becomes part of the sciatic nerve
  • There are several varieties of lumbosacral plexus:
    • The most common is a “prefixed” plexus, including all or part of T12
    • A “normal” plexus
    • A “postfixed” plexus
    • Or even a plexus spread in both directions:
      • These anatomical variations can affect regional anesthesia practice because of variations in motor and sensory distributions
  • The division into two planes of the lumbosacral plexus is less clear than for the brachial plexus
  • The two terminal branches of the lumbar plexus are the femoral nerve and obturator nerve, which correspond, respectively, to the dorsal and the ventral layers
  • For the sacral plexus, the tibial nerve is the ventral layer and the common peroneal nerve the dorsal layer
  • The layout of the main nerves of the lumbosacral plexus requires the use of combined blocks for anesthesia of the lower limb

++
Figure 139-1. Lumbosacral Plexus
Graphic Jump Location
++
Figure 139-2. Lumbosacral Plexus and Muscle Innervation
Graphic Jump Location

Want remote access to your institution's subscription?

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.

Ok

About MyAccess

If your institution subscribes to this resource, and you don't have a MyAccess profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus.

Subscription Options

AccessAnesthesiology Full Site: One-Year Subscription

Connect to the full suite of AccessAnesthesiology content and resources including procedural videos, interactive self-assessment, real-life cases, 20+ textbooks, and more

$995 USD
Buy Now

Pay Per View: Timed Access to all of AccessAnesthesiology

24 Hour Subscription $34.95

Buy Now

48 Hour Subscription $54.95

Buy Now

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.