Lumbosacral Plexus: Overview

00:01 In this lecture, we're going to look at the lumbosacral plexus.

00:05 So let's start off by having a look at a broad overview of the large number of nerves that we have that make up the lumbar sacral plexus.

00:16 First of all, let's remind ourselves that these are coming from spinal cord segments all the way down from the lumbar and sacral region and even into the coccygeal region.

00:25 So first of all, we have the lumbar plexus coming very much from T12 down to L4.

00:31 So you see the lumbar plexus here, then we have part of the sacral plexus, which is some have L4, L5, down all the way to S1, S2, S3, S4.

00:41 And then we have a bit of a coccygeal plexus which finishes off the spinal cord segments with a bit of S4, bit of S5, and some of the coccygeal spinal cord segments.

00:51 But essentially, we have the spinal cord segments giving rise to a whole series of nerves that are coming away from the spinal cord passing through the intervertebral foramen and then entering into the abdominal cavity, ultimately then passing through the pelvis as well into the lower limb.

01:09 So let's start by looking at the lumbar plexus.

01:12 The lumbar plexus as you can see a spanning from the lower thoracic spinal cord segment all the way down through the lumbar spinal cord segments.

01:19 And it gives rise to a whole series of nerves, some of which we'll cover later on, and some of which you may well have heard already.

01:27 We don't need to therefore go into great detail about them.

01:31 But coming away from the lumbar plexus, we have the iliohypogastric nerve, that ilioinguinal nerve, the genitofemoral nerve that will like to split into genital and femoral branches, we have the lateral cutaneous nerve, we also have the femoral nerve, and the obturator nerve.

01:49 So these nerves are all coming away from the lumbar plexus.

01:53 If we then just move further down and look at the sacral plexus, we can see the sacral plexus very similarly is giving rise to a whole series of spinal nerves that will leave through the intervertebral foramen and go through the pelvis, the abdomen, to enter into the thigh.

02:09 And here we can see the sacral plexus coming from around the lower aspects of the lumbar spinal cord segments and running throughout most of the sacral spinal cord segments.

02:19 We have nerves such as the superior and inferior gluteal nerves.

02:23 We have the sciatic nerve and it's two constituent parts, the common fibular, and the tibial nerve respectively.

02:31 We also have the posterior femoral cutaneous nerve, and we can see here we have the pudendal nerve.

02:37 So all these nerves will carry motor and sensory branches except the cutaneous nerves that just carry that sensory information, but they will be passing to muscular tissue and to serve the skin with sensation.

02:50 If we then finally move on to the coccygeal plexus, this is really the most inferior tip of this aspect we're looking at.

02:58 Residing really with the lower sacral spinal cord segments.

03:01 And that spinal cord segment which is the coccygeal aspect.

03:05 And this is a coccygeal plexus really coming from here, we have the anococcygeal nerves and we'll talk about those very much towards the end of this presentation.