 Hey everybody, Dr. O. This is going to be a real short video, so I've already talked about spinal nerves, I've already talked about peripheral nerves, but it's one last thing to talk about. When you take these complex interwoven patterns of these spinal nerves that fuse together, they're going to form these larger structures called nerve plexuses. So you see here on the screen the cervical and brachial plexus, I'll also show you the lumbar and sacral in just a second. So there's often a little bit of disagreement as far as where one stops, where one starts just because of this complex nature. The cervical plexus is generally going to be from C1 to C5, and this cervical plexus is going to innervate the muscles of the neck, the thoracic cavity, and the diaphragm. So that's a very important one. The brachial plexus is probably the one we talk about the most. I generally say it's from C5 to T1, here you see it labeled C6 to T1, but this is going to control your pectoral girdle, excuse me, your pectoral girdle and your upper limb, so that's the brachial plexus. That's one that can be injured when sports injuries fall, those types of things. When you see the lumbar and sacral plexus, oftentimes this is just called the lumbosacral plexus because there is so much connection between the two. But the lumbar plexus, here you see it from L1 to L5. You also might see it from T12 to L4 as far as the spinal segments involved in the lumbar plexus. Then the sacral plexus, here you see it from S1 to S5. I've also seen that from L4 to S4. So as a group, the lumbar and sacral plexuses, they control your pelvic girdle and the entire lower limb. All right, so those are your four nerve plexuses. Just want to make sure you've heard those terms. We generally talk more about peripheral nerves than these plexuses here, though. I hope this helps. Have a wonderful day. Be blessed.