so guys sciatica one of the most common conditions we see in musculosceletal physiotherapy so in this video we're going to show you the anatomy of the sciatic nerve and tell you how that Anatomy relates to symptoms that patients might present with so if you're ready let's dive in hey guys CARiD here welcome back to clinical physio we've got our 3D Anatomy model on the screen to show you all the key features of the sciatic nerve and how this relates to when your patient has sciatica so let's go through it so as you can imagine the sciatic nerve is a super important nerve in the leg and it's one of the biggest as well and therefore it's no surprise that it has a lot of spinal Innovation from different spine nerve Roots so we know that the sciatic nerve is derived from The L4 L5 S1 S2 and S3 nerve roots and in particular we look at these L4 L5 and S1 levels as the most common ones that might get irritated when your patient has back pain so for example if your patient has a discernation at The L4 L5 or L5 S1 level naturally that can compress on one of those nerve roots and irritate the sciatic nerve so from there we know that the sciatic nerve runs through an important part of the pelvis called the sciatic Notch and then it runs underneath or deep to a super important muscle the piriformis muscle now if you believe everything you see on social media you'll think to yourself that the piriformis muscle is always compressing that sciatic nerve causing symptoms of pain pins and needles numbness down the leg however the reality is is that the piriformis muscle doesn't actually do it that often research has shown that there's loads of other structures such as the gelli muscles the obturator muscles the isop femoral joint the sacr tuberous ligament that all are present within that gluty region and all could have an impact on the sciatic nerve and so instead a term that you'll see have seen in the past piriformis syndrome has actually been replaced by Deep Glu or pain syndrome this idea that actually it could be any number of structures in the glut region that can cause stica therefore it's more of an umbrella term but in saying that it's suggested that deep glucal pain syndrome is only responsible for sciatica between 0.3 and 6% of the time so not very often at all so please do bear that in mind so from there we know that the sciatic nerve runs down the back of the leg this is super important because it tells us that when patients have sciatica it's pain in the back of the leg that they may experience erience with either a burning sensation a shooting pain an electric pain or perhaps pins and needles or numbness in that region so when patients come to you and say yeah I've got pain on the front of my leg that isn't necessarily related to sciatica because the sciatic nerve doesn't run there it runs down the back of the leg and from there the sciatic nerve branches into two really important divisions which are the tibial nerve and the common perinal nerve and so what we're going to do is show you these two different divisions and how they might influence sciatica so the tibial nerve is the first branch that we're going to talk about and as you can see it runs from the sciatic nerve straight down the back of the leg towards the foot and it innovates lots of key muscles in the back of the leg such as the gastrus muscle the cus muscle and plantaris the key plant flexors of the foot as well as if we move further down the leg tibialis posterior flexa digitorum longus and flexa hucus longus so what do you notice about all those key muscles apart from the fact that they're in the back of the leg well the key thing is that they all have an influence on planter flexion and foot flexion therefore when our patients have sciatica look out for if they have a weakness in the plant of flexion or foot flexion movements because as you can see the tibial nerve is the branch of the sciatic nerve which supplies all of those key muscles so therefore look out for when your patients don't have that plant def flexion strength or when you ask them to do a heel raise and they can't push up onto their toes now you know why it's because those muscles are innovated by the tibial nerve a branch of the sciatic nerve and when the sciatic nerve is dysfunctional it means that those muscles don't get the strength that they need right so let's head back to the posterior knee where we saw the sciatic nerve branching into the tibial nerve and the common perinal nerve and let's look at the common perinal nerve in more detail so this particular nerve divides further into two really important nerves which are the Deep perinal nerve and The Superficial perinal nerve now you might also hear these different nerves described as the common fibula nerve the Deep fibular nerve and The Superficial fibula nerve you can use perinal or fibular they both mean the same thing you can use them both in your practice now a really important phrase that I use to remember what the deep and superficial perinal nerve do in terms of muscle Innovation so the phrase is ADLs now of course you'll be very familiar that ADL sometimes stands for activities of daily living but I also use it to remember anterior deep lateral super superficial that tells me that the muscles of the anterior tibia are supplied by the Deep perinal nerve and the lateral muscles around the fibula are supplied by The Superficial perinal nerve so anterior deep means that the anterior muscle supplied by Deep perinal nerve lateral superficial means the lateral muscle supplied by The Superficial perinal nerve so therefore if we look at that deep perinal nerve in more detail we can see that it innovates muscles like tibialis anterior extensor hucus longus and extensor digitorum longus what do you notice about these these are all dorsiflexors of the foot so when your patient comes in with back pain paining running down the leg and they have a foot drop now you know why it's because the sciatic nerve goes on to supply the Deep perinal nerve and if the Deep perinal nerve is dysfunctional your patient will have a foot drop so that is super important a really important sign to look out for when your patient has sciatica and then if we look at those lateral muscles as we said lateral superficial so those lateral muscles are supplied by The Superficial perinal nerve so there we're thinking about muscles such as perus longus and perus brevis also known as fibularis longus and fibularis brevis and these muscles e the foot so again if your patient presents with back pain pain running down the leg and they have weakness in ersion now you know why it's because the superficial perinal nerve innovates these important muscles and when that nerve is dysfunctional it means that they don't have that ersion strength so finally anterior deep lateral superficial to help you remember what those key nerves innovate and of course they both stem from the sciatic nerve so a couple of other clinical observations to make as we said earlier the sciatic nerve is derived from the spinal levels L4 L5 S1 S2 and S3 therefore we know that the ankle reflex supplies or tests The Reflex at the spinal level S1 S2 and therefore look out for when your patients have a reduction in this reflex when they have sciatica and furthermore when we think about the different dermatomal patterns we can look at L4 which runs on the medial aspect of the tibia we can see L5 runs from the fibula down towards the first digit and S1 runs around the lateral surface of the foot now most commonly we see L5 and S1 dermatomes affected here so if your patient has pins and needles and numbness running down to their foot particularly the lateral side of the foot once again we might think about that sciatic nerve so look out for those super super important as a part of your picture for your patient who has sciatica so everyone I really hope you've enjoyed this video if you have please support us by Smashing that like button and subscribing to the channel remember we've got loads more resources on our Instagram account @ clinical Physio and on our membership website member. clinical phys. comom a brilliant resource for physiotherapists looking to improve their skills my name is CARiD thank you so much for watching see you soon here on clinical physio