The Muscle that Unlocks the Knee: Screw Home Mechanism Explained | Corporis

[@ianjohnson4987]

78 year old retired doctor studying foot health here. What a brilliant video. Thank you. Liked and subscribed

[@jarelmarcelin4985]

I am a biomedical engineering student who just took anatomy and physiology this past summer! I am considering of double majoring in biomedical engineering and athletic training. Your videos are very detailed and interactive. I definitely have used them to help me through the multiple systems in the human body!

[@truthbetold711]

What can you recommend for a locked knee due to a torn meniscus?

[@thabomwanandimai9936]

Hi Jarel, did you take up the double major? I'm a PT student, biomedical engineering sounds interesting

[@CrochetIsLife54]

I’m nearly 70 and fractured my patella. I tripped and fell onto the knee, which was in multiple pieces. I’m a reasonably decent layperson when it comes to scientific jargon, but this is my first time learning about bones, tendons, and a rather complicated joint. I thought my PT will go better if I learn how the knee works and understand better how the exercises improve function. Thanks for providing educational videos.

[@snorlax9258]

how are you can you bend it already?

[@Bdubtheblack]

I'm an SPT who has an exam tomorrow over the lower extremity. You're a godsend!

[@dt5092]

I’m an occupational health researcher looking at repetitive stress injuries. Your videos have been so helpful in deciphering physical therapy notes! Absolute life saver!

[@tarrySubstance]

I am an Information Technology student who is also a fan of learning anatomy and physiology. The human body is a work of art.

[@1unsung971]

A work of evolution

[@pghparkins]

I am a middle-aged nerd who loves learning. I know the body "just knows" how to move proper muscles in all kinds of ways, but for some reason that little muscle that twists the knee in the right way depending on whether we are sitting or standing without us ever having to think about it was really fascinating.

[@Corporis]

I thought so too :) It's one of those cool consequences of bipedalism

[@NEETmedicalGK]

@@Corporis Subscribe and Thanks Sir.

[@1unsung971]

The Nervous system is the system that "just knows." Muscles are merely the slaves of the CNS.

You are not a nerd but a wise guy

[@nikevisor54]

Watching this while rehabbing a knee injury👌

[@emil1063]

Same :/

[@Corporis]

A new meaning to the phrase "My body is ready"

[@PaulSmith-pr7pv]

I’m also rehabbing an injury but I also love this content. I don’t work in the medical field but I’d love to change jobs one day.

[@spectraanon]

Same buddy

[@saraomar8621]

I wanna know how can I use the practically in rehabilitation ? I am frankly fascinated but then what? Tell meeeeeeeeeeee how can i use that greatnesssss

[@orungbejatoluwani7363]

Finally found a video the explains knee locking properly

[@DJ-bo4pz]

Wow,....I didn't know a channel like this existed. I injured my knee, and I was trying to understand how knee works, and what part of it could I have hurt. My guess is that I have sprained my popliteus muscle because my knee hurts when I stand up from a sitting position. Once I am standing, it barely hurts (which is when the popliteus is mostly contracted and not under tensile load). I might be wrong, I am not a doctor but your video is a great help for us non-medicos to understand basic human anatomy in context of daily activities that our schools should have taught us. May you get 10 million subscribers.

[@camver100]

Oh man this is going to be a huge channel , those animations and model explanations and well articulated definitions are unlike anything I’ve seen

[@pierobuhytron3670]

Dude, this is by far the best Anatomy video I've ever seen. Great teaching methodology

[@aafreenimtiaz901]

I am a bachelor of physiotherapy student,i like ur way of talking ,ur teaching style , overall thumbs up 👍🫀🤗 appreciate ur efforts and the mankind to the 🌎

[@AlexisAcosta-wr6kf]

Good stuff man you actually tap into how a person actually learns not just coveying information 👌

[@Corporis]

Thank you! I take pride in my teaching style

[@KatherineCarrier]

Thanks! Hey! I’m a yoga teacher and this has made me an anatomy nerd :) this is so helpful!

[@bestonemusic]

Do yogis eat a lot of yogurt?

[@ishaqureshi402]

Never been so concentrated on a video than this. You had me along every second and now that I understand it, it really is Mind-blowing. Thank You.

[@sidrens5292]

Excellent presentation!!! I am a Sports Therapy student at University in UK. These videos are some of the best around.

[@mikew370]

Thank you. I will be back. I had a tibia fibula break, with a tibial plateau fracture that has been screwed and plated and a single screw inserted down into the fibula from the top. Seeing how it all works has helped me understand why I am still struggling with some simple things like leg curls and sitting knee extensions. The plateau fracture tore the cartilage and it seems to have gone right through where the patella tendon is attached. I almost certainly snapped my pcl and definitely damaged my mcl. My lcl was fortunately still attached to the end of the fibula when they screwed it back on. This video has really helped me understand it. Thanks

[@maxjordan2625]

Wow i learned so much! Thank you! Tore my lateral meniscus and got a stitch in it/got it trimmed and after 2 months I can't quite lockout my knee still and this helps me picture what's happening! I can extend it just maybe 1 degree past where the hamstrings relinquish control to the popliteus, or so it feels... Was a scary feeling but this explained it so perfectly.

[@gracemitchell9191]

Thank you, I am a biomechanics instructor and this is the only good video on this topic on KZbin!

[@xw591]

Wow! Definitely learned something. My knee is achy after a workout yesterday and this helps me make sense of who's on first.

[@claytonmagnuson1677]

I'm a PTA student, just learned about the screw home mechanism. I love your videos! You explain stuff really well and make it easy to comprehend.

[@yarenengin5630]

i ' m physical therapy student and i think i'm totally fall in love with this channel

[@cecilia5103]

I am massage therapy student and your videos are amazing!! The academy I attend reads from our book(s)...they don't really teach! Your videos have helped pull everything together for me and make more sense!! :) Thank you for creating!

[@marka.schlueter9918]

Just found this and it is a great explanation. I went to my PT doc and was having issues with my knee. With my legs hanging off the table he said I have an issue with the "screw home mechanism". The what??? It took a lot of time, but he kept pulling down and slightly turning my lower leg when I finally heard or felt a tiny "pop". Did he release something? Not sure of the jargon but after several more visits my leg felt normal again. He said that in his 15 years of teaching and attending to clients, it's the first one he's ever seen. We surmised that it probably occurred in Jiu Jitsu class. Thanks for the clear illustration of the SHM.

[@ravihls]

wow. great information i had a logitudinal tear in lateral menisci ahd the surgery for the same. but my knee was locked and cant extend that final few degrees. My physio did all she could but this is a new iformation that i can share with her - hope i will get a fully extended knee one day

[@OliviaFlores-m1]

THANK YOU!!! I could not understand this mechanism whatsoever until after watching this video

[@shagungarg4091]

I am a physiotherapist student .For us, Its very important concept to understand and i already saw lots of vedios but i never get it before.Thanks to u, today i understand whole concept. Thanks sir

[@arthur1010123]

Fantastic! I'm a physiotherapy student from the Netherlands, and this video is really helpful for my studies. Thanks a lot!

[@saamazul]

Thanks for your explanation, i'm currently studying for the NPTE and this video help me a lot.

[@chazmuska]

NASM certifed PT. Im fascinated learning everything about the human body. Its truly a work of art!

[@justaguy328]

That's absolutely astonishing engineering. Crazy that people think an unguided process could produce such a thing. We are wonderfully made!

[@1unsung971]

Evolution is random mutation. You need to understand that to understand human function and physiology

[@xw591]

Yeah, "made." Becayse tge homosapiens that couldn't walk didn't reproduce. Unfortunately for you, the ones that couldn't think DID reproduce, and here you are.

[@nicholashockings9584]

Hello Patrick. I have to say, I've only just discovered your content, but I absolutely love it. I've already signed up to your Patreon and I sincerely you hope you continue making more science education videos. I'm a high school science teacher and former medical research assistant. Like yourself, I'm passionate about teaching science as you are. I often create content for my students and I'm really interested in finding out how you make your videos. Tbh, I'd actually like my students to learn how to make similar videos through their own second hand research. Anyway, keep up the great work.

[@felixslytherin6567]

Your content is always on what i need the most Are you my guardian angle❤

[@AkbotaZhailkhan]

first year med student here TT have exam tomorrow and got stuck on knee joint... thank you so much! really cleared up a lot of things for me

[@precisecovers2551]

MRI student! I've watched your videos before, I specifically remember your anatomy and physiology of the kidneys video, which helped a lot! Cheers!

[@KC-wm6tr]

2:36 cruciate ligament PCL tightens and helps glide tibia anterorly during extension ACL tightens and helps glide tibia posteriorly during flexion

[@KC-wm6tr]

3:52 popliteus: lateral meniscus --> medial posterior tibia for IR tibia (open chain) / ER femur (close chain)

[@lesleysprake1045]

Wow that was fascinating ! It’s the only thing I’ve seen focusing on this little muscle ! I’m fascinated

[@patrickbianconi1817]

From another physio, great job and great explanation with this video on a complex topic

[@agnes4901]

i'm a pt trying to learn the terms in corrective exercise course, thanks for the video, it's quite helpful! 🙂

[@melissaadrian-w2j]

Great video and I am a SPT! Very well done and helpful for understanding difficult anatomy concepts! thank you!

[@PFMediaServices]

I am just a gal on the internet who loves learning things and everything in this video was new to me, except the locking mechanism seemed incredibly familiar. Because after falling down a rabbit hole about amputation and prosthetics, I recognize it as a "feature" that's becoming available in newer leg prostheses! If I recall, for a more normal gait, simpler ones require a sort of kick forward with every step that takes some getting used to, (apparently going down his and stairs is quite an ordeal to start with) and now there are models that can semi-lock with a button or switch toggle for walking vs. standing vs. sitting (some are toggled with a set number of toe taps, which is very cool and fast less intrusive) and higher-end models have sensors to enable/disable this automatically? I think? Anyway, what I'm saying is how incredible our bodies are, just all on their own without having to think about it, and how challenging it is to reproduce many of the little aspects we take for granted. Wow.

[@AbigailSnyder-js2mc]

In my last year of PT school, taking the boards soon, and this was helpful-thank you!

[@someonesson6222]

I'm a Physical therapist assistant at a hospital in Central Phoenix Az. Years ago I strained my left popliteal muscle, and I currently am having an issue with left popliteal muscle again. Thanks for the video!!

[@Corporis]

My pleasure! I actually used to work in a clinic in Phoenix as well during grad school!

[@gigihoo2978]

Finally 😩some one explain Screw home mechanism for me 🙏 Thanks!

[@anupkumar5662]

This was amazing . I am a strength coach who has to deal with athletes and general clientele of varying sports, levels , abilities and injury histories. As part of my own learning and growth I made it a point to keep exploring varying fields of learning for better performance. Anatomy is one of my weakest areas ... I've always found it complexly written and explained. I did not make much headway for these reasons into the depths of joint mechanics. This to date is by far the greatest explanation of some of the knee joint characteristics that I have ever come across. Thank you for this. Keep up the good work. SUBSCRIBED !!!!!!

[@1unsung971]

How can you be a strength coach if your knowledge of anatomy is weak???? You should immediately refund all your clients to date. That's immoral and unethical

[@henriettkoti7766]

I am a personal trainer, with ambitions to study sports rehabilitation and physiotherapy one day, and your anatomy videos are really inspiring me to pursue these dreams👣 Your videos are truly amazing, I recommend it every time when a colleague or another PT student asks my advice for the best anatomy YT channel. Keep going Patrick, your videos make a huge impact ❤️

[@kevjumbaz]

Screw home mechanism = ER of the tibia during terminal knee extension to provide stability. Popliteus helps to unlock screw home mechanism stability: 1. CKC = ER femur on tibia 2. OKC = IR tibia on femur

[@MissDollyDimples]

I am a first year Physiotherapy student & I love your content! 🇬🇧

[@ShauntelleCannon]

Extremely helpful video. Thanks so much! Right when I needed it as an audiologist studying for a biomechanics quiz and no background of anatomy outside of the ear.

[@ruturaval1829]

I am a first year physiotherapy student and this video is so useful for my anatomy exams.

[@Waybear]

I passed my MBLEx thanks to your channel. Thank you so much!! Keep up the great work!!

[@Corporis]

I appreciate the kind words, congratulations!

[@pandoraefretum]

Good clip ; good question. I am a 59 year old violinist (now teaching) who suffered a major stroke 1.5 years ago

[@beanface8586]

As a student RMT, this video was very helpful in explaining this mechanism in a simple way. Thank you so much!

[@itszach930]

Thankyou! By far the best video explaining this!

[@Jazoolee]

Just a regular athletic/engineering dude who is interested in the anatomy of the human body😍 Love your videos man!

[@crystalfavorito7820]

At 2:36, isn't this reversed? I thought the ACL tightens during extension, and the PCL tightens during flexion

[@MAmeer-fr2hp]

I'm a medical student and i really love your content. Keep up the great work!

[@pawesuliga8815]

I really like all of your work! Currently I am working on pathological defects in pig's muscles. I am focusing on M.Semimebranosus and M.Adductor. Here the importance comes with their function but I also compare pigs that have a different level of movement availability ( free-roaming vs conventionally kept). Thank you for your informative videos!

[@chpapermagic1370]

Thank you for the explanation, fo me i have a popliteous pain, it is difficult for me to band my right knee, and am a basketball Player.

[@ROMANEMPIRE69]

I have right internal knee pain. Been seeing a chiro and doing pt. Still pain. Gotta get an mri to rule out any tears or other damages

[@tehreemfatima8067]

Thanks ....you make it easier to understand

[@nutritional_yeet]

OTS here, this vid helped a lot in understanding what is actually going on here

[@autisticcormorant6881]

oh man if only there was a video for each muscle anatomy would be a breeze. Great video thanks a lot! Hopefully m. popliteus comes up on the exam

[@rpc1605]

Very technical, but also very interesting. I was in a car accident and was thrown forward on the tarmac. My right knee took a hard knock while rolling to a standstill. When I tried to stand up, my knee just folded under me. It wouldn't take any weight. It swelled profusely.

[@user-rp4pb3oo5y]

Thank you for your very helpful breakdown of the screw home mechanism! Since the sartorius helps to medially rotate the tibia when the knee is in a flexed position, does the sartorius also play a role in bringing the knee out of full extension? Otherwise, when else does the medial rotation of the knee by the sartorius take place?

[@rph_redacted]

I am a pharmacist who loves learning about anatomy, physiology, kinesiology and fitness in general.

[@jhmho]

thanks for the explaination! i am a physiotherapy year one student

[@Corporis]

Happy to help! Best of luck in your studies

[@drSJV]

Thank you, such an amazing video!

[@grampafitness9732]

Personal trainer here ... one who got physically active in my late forties because I have pre-arthritic deterioration in the meniscus of one knee. Had to learn some basic anatomy and kinesiology for my certification, picking up more as I go along because it helps me stay within my scope of practice as a non-expert but lets me tell clients "this sounds like it might be X, but remember my training has VERY serious limits: please see a physical therapist or doctor to find out what's actually happening, and get advice on what I should or shouldn't encourage you to do." At least two of my clients have knee issues of their own. The more I know, the more I hope to be able to help them prevent further issues, without adding to their woes by suggesting things that would be bad for them.

[@1unsung971]

You should know this stuff already!!!!!! Go to Physiotutors. A little knowledge is enough to hurt people.

[@darlenawade-williams579]

Hi, my name is Darlene, and my right knee has been locked straight for about eight years. I’ve seen an Orthopedic surgeon for years. However, he explained that it would not have much difference if I underwent a knee replacement surgery. He claims I wouldn’t have too much more movement in my knee than I have now. Is there another option for me to get my knee unlocked? Most of the time, there’s no pain. Thank you for whatever advice you can offer me.😊

[@glennshibu5776]

much love from a struggling physio student

[@tomtenthij5676]

Thank you SO much! this video was very helpful!! :D

[@onrdmr5454]

Thank you for valuable info👍

[@abdulkadir8358]

Thank you so much

[@nordicathletics]

Amazing quality video

[@jerrysegal2903]

found you by accident but great stuff. A question-the screw home mechanism is the reason to not fully lockout on a leg extension machine since it forces the condyles to grate against each other?

[@gasdive]

I'm an ecologist, but I'm fascinated by the evolution of this structure. Our closest relatives, chimps and bonobos, don't have it, so it's a very recent development.

[@leenalhaj.]

2:36 I think u said the opposite regards to ACL/PCL function

[@Corporis]

Before researching for this video, I thought it was like that too. But according to Physiopedia, it's the claim I made in this video: *During knee extension, tibia rolls anteriorly, elongating the PCL and the PCL’s pull on tibia, causes it to glide anteriorly. During knee flexion tibia rolls posteriorly, elongating the ACL and it is the ACL’s pull on tibia, that causes it to glide posteriorly.* www.physio-pedia.com/Screw_Home_Mechanism_of_The_Knee_Joint

[@leenalhaj.]

@@Corporis thanks

[@thomasdayooshadogan1045]

Thanks Corporis, u are very nice.

[@anielamarya]

hey in a registered nurse. I also do olympic weightlifting. I “sprained my patellar tendon”, that’s what they told me when it happend. it’s basically completely rehabbed the injury was 8 years ago but it feels weird when i extend it still. wondering if maybe i need to balance out all the squatting w something that flexes my knee the opposite direction?

[@SuperLameStuff]

I’m a dancer and I am trying to figure out why my left knee is always in pain. I have patellar tendinitis. I been using a 45lb bench bar as a foam roller on my quad to give my patella slack. I also roll my piriformis with a lacrosse ball for slack on my IT band. Currently taking a couple weeks off to recover.

[@Kingx90]

My feet were twisted outward HARD multiple times by a massage therapist and I have been in pain for months. X-RAY and MRIs came back with no observed injuries. Can I ever fully recover? It’s been 3 months, I’m only maybe in half the pain I was originally in.

[@cpt.battlecock5264]

Wouldnt locking of the knee not occur because of an internal rotation, Like the medial condyle twists medially backwards, And the unlocking be done by external rotation with the lateral condyle pulling backwards then medially?

[@bildadolemukol-dt4ym]

MBChB Level I here, found the video quite enlightening

[@Instakateor]

I’m trying to learn more and no doctors have been able to help me. My chiropractor mentioned to me my problem is the screw home mechanism. I came across this video and have learned a little bit, but am so curious as to why the outer part of my knee starts hurting after hiking 6+miles. I’m fine going up hill but the moment I go down hill I can not bend my knees or else my leg gets stuck in pain- just breathing causing too much movement and I’m left in pain unable to move for 2 hours until it “slides back in” to regular position I can then bend my knee. Popliteus is almost visibly out of place as this happens. I’m insanely uncomfortable laying on my stomach and anyone getting near me, I have to bend my legs up at the scare or risk someone touches my legs it will throw my screw home mechanism out of place also. Any info would be so greatly appreciated! I appreciate your video so much!

[@Instakateor]

I’m no medical student so maybe it’s not the popliteus, but something on the very outer kinda behind the knee seems out of place. If I can stand the pain sometimes slightly bending my foot upward seems to help while I’m laying on the ground locked up in pain, but it’s very very small movements I’m able to make with my foot. This has been going on since I was a child and yes I had to wear special shoe inserts as a child for my feet not being straight when I walked and I have ITband pain starting about my hip that goes to my ankle. Movements to “help” sciatica pain only inflame things and make it worse.

[@buthkoludom8th758]

Great video!

[@dietformea]

Excellent

[@myfeliscatus]

Well done.

[@StephenSambo-j9q]

Hi sir..... I have a little question about my knee which constantly bother me...... OK here it is........ I did an X-ray of my knee today, which I got the injury from playing football (armature). The doctor said dat they hav to run a surgery which that I have a bone growth..... Am scared of loosing my leg.... Can't there be anyway out? 🙏😭

[@tmonce]

I’m a personal trainer that just loves learning as much as I can to help me better understand the movements and functions of the human body.

[@sheilavives1137]

After a bad fall and right knee injury I was unable to walk and cannot stand but for a few seconds if I put the weight and stress on the back leg muscles. (My left knee was already in bad shape) If I try to walk, my legs try to collapse downward and the legs/knees wobble and shift drastically side to side. This causes more pain and more damage. What kind of injuries would cause this? I want to know why I cannot walk. I have not been able to get help or answers from an orthopedic. The last one would not see me unless I did standing weight bearing x-rays, but I cannot stand or maneuver for those type of x-rays.

[@aheartofworship27]

My surgeon said I needed to liste loosen the popleteus tendon. It hurts though. Any good videos on this?

[@irenemielke1713]

I had a locked knee for 2 months, and finally had a surgery last month. My knee is totally still feeling locked. I'm watching videos trying to start rehab before I go to the physio therapist. I am determined to get better by September. I feel hopeless a lot of days :(.

[@pinkelephant2834]

Go hard in therapy!!! I'm a year and 7 months from a PCL surgery and I cannot walk without a cane 🙈💔 I have a limp... Break up that scar tissue 😘

[@aysugano1]

I absolutely loved this explanation. I am a dance science ballet coach. I wanted to ask you something in a DM if we could. Thanks so much!

[@milliechalk8398]

Recovering from fractured patella surgery with screws. I can have 120 range of motion but soon as leg is straight Knee freezes up. What’s happening?

[@fireblade9005]

Hi ..my left knee locks when im sitting down ..especially if im sitting with my knee more than 90 degs..I can unlock it by pressing the left side of the knee (outer side) where the hamstrings are located ..its definitely getting worse ..Im 57 and dont want to have a new knee !..So are there any exercises i can do for this ? Thankyou

[@drdollysingh1525]

Hi, Nice information

[@aakashbansal8925]

I just broke my patella and had surgery 3 weeks ago and now as the swelling is going away its getting more and more obvious that my patella tendon has moved to the right and i was actually expecting this as i stil cant raise my leg at all.....please sort it out for me whats really going on and what should i do

[@JoeMoran1968]

stroke survivor my though i have control i di have knee pain what can i do to relieve the pain/