Spinal Nerves – Anatomy of the Nervous System (Nursing)

00:00 So now that we've discussed the different spinal cord segments, let's talk about the spinal nerves.

00:07 The spinal nerves are what connects the central nervous system to the sensory receptors, muscles and glands of the body.

00:16 The spinal nerves are considered a part of the peripheral nervous system.

00:22 There are 31 pairs of spinal nerves.

00:25 And the anterior and posterior roots attach a spinal nerve to a segment of the spinal cord.

00:33 If we take a closer look at the individual parts of the spinal nerves, you will find that there are 8 pairs of cervical nerves, 12 pairs of thoracic nerves, 5 pairs of lumbar nerves, 5 pairs of sacral nerves and one pair of coccygeal nerves.

00:56 Recall these different names correspond to the vertebrae where the spinal nerves will exit from intervertebral foramina.

01:07 So if we take a closer look at the anatomy of the spinal nerves, starting with the connective tissue layers that cover them, you will find that there are three main connective tissue layers.

01:20 First, you have the epineurium which is going to surround the entire nerve.

01:27 Inside, we have bundles of axons referred to as fascicles.

01:34 The connective tissue layer covering the fascicles is referred to as the perineurium.

01:41 And then finally, each individual axon contains a connective tissue covering called the endoneurium.

01:49 And together, this transverse section shows the coverings of the spinal nerve.

01:56 So along with the spinal nerves as they exit from the intervertebral foramen, the spinal nerve is going to divide into several brances known as rami.

02:08 There's the dorsal rami which is going to serve the dorsal portion of the trunk and goes toward the posterior portion of the body.

02:19 Then you have the ventral ramus which is going to serve the ventral portion or anterior portion of the trunk, and the upper and lower limbs.

02:30 You also have meningeal branches.

02:33 These branches from the spinal nerves go from the spinal nerve and then re-enter back to the spinal cord through the intervertebral foramen.

02:44 These supply the vertebrae, the vertebral ligaments, blood vessels at the spinal cord and the meninges.

02:54 And then finally, for the autonomic nervous system, we have the rami communicantes.

03:00 These are going to contain our autonomic nerves.