[Music] so let's talk a little bit about disc herniations and locations of disc herniations central discs true central discs which come you know directly out of the center of the posterior aspect of the disc are really actually quite rare the most common type of disc herniation we see is this one in the top left corner which is the paracentral disc herniation you guys may remember that the reason you get a pair of central disc herniation is because the posterior longitudinal ligament is running in the posterior aspect of the disc so it reinforces the nucleus is centrally but as you work out laterally you don't get as much reinforcement from the posterior longitudinal ligament so the disc will find the path of least resistance and makes its way out very essentially the second picture is a lateral or a foraminal disc so this is truly in the foramen this can still be accomplished surgically through a traditional laminotomy approach and then the one of the less common types of discrimination is this far lateral disc herniation where you can see the disc is actually herniated outside of the spinal canal outside of the foramen but can still be hitting that exiting nerve root as it comes out of the foramen and that's about 10 to 15 percent of cases i'll talk a little bit about surgery for those and kind of what the differences between the two are so just a traditional anatomic picture here this is the l three four vertebrae you're gonna see this a couple of times as we go through the talk here what we what i've done here is you can see the exiting nerve root above that's this nerve as it comes out of the foramen and then the traversing nerve root below i i always describe this as imagine cars getting off the freeway so if you think of the nerve roots as you know they're going to come to their exit point they're going to come to the spot on the freeway freeway where they want to get off and go to their destination the nerves will continue to line up and as they get closer to their destination they move more and more to the outside ultimately end up out here as far laterally as possible within the spinal canal and then they go down below the pedicle and out the foramen so just think of it as cars kind of working their way from you know the innermost lane of the highway all the way to the right to get out of the traffic and that's why it's important to understand this relationship because the paracentral disc herniation typically compresses the traversing nerve root and this is why when you talk about you know an l-34 disc herniation paracentral disc herniation you're talking about compression of the l4 nerve root this is the l3 nerve root as it comes out of the spine here this is the l4 nerve it is it traverses down it comes out under the l4 pedicle so again this is why you get that compression of the traversing nerve root far lateral disc herniation really gives you the exact opposite you're now compressing the exiting nerve root so it's important to know that based on what to see on your imaging where people's symptoms are and you know putting the whole picture together before you proceed with any kind of procedure types of disc herniation this is more kind of a nomenclature sort of uh portion of this but you know treating these are very similar regardless of what type of disc herniation but you know simple degenerative disc bulge you can see there in the top left corner here prolapse is where you get that you know worsening uh kind of bulging of the disc potentially causing issue compression of the nerve root extrusion is where you get that you know disc material completely coming out of the annulus and then sequestration is where the entire nucleus comes out and is ultimately separated from the other contents of the center and the disc hey everyone ryan rad here from neurosurgerytraining.org if you like that video subscribe and donate to keep our content available for medical students across the world