The Muscle that Unlocks the Knee: Screw Home Mechanism Explained | Corporis
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- Опубліковано 9 січ 2022
- While it seems like our knees move in a straightforward way (bending and straightening), your tibia actually rotates a little bit through the last few degrees of extension. This is called the screw home mechanism. In this video, I'll show you how it works.
☠️NONE OF THE INFORMATION IN THIS VIDEO SHOULD BE USED AS MEDICAL ADVICE OR OPINION. IT IS FOR GENERAL EDUCATION AND ENTERTAINMENT☠️
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💊A B O U T 💊
Hi, I’m Patrick. I’m a freelance science writer based in the San Francisco Bay Area. I hold a bachelor’s degree in Athletic Training and a master’s in clinical exercise physiology. I used to work in the clinical setting as a certified athletic trainer, physical therapy aide, and a certified strength and conditioning specialist. After working in the clinical setting, I went back to school and became a teacher. The goal of my content is to help normal people, not just pre-med students, learn about the human body. That might mean explaining a topic from an anatomy class or exploring a topic from medical history.
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#corporis #anatomy
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.
Watching this while rehabbing a knee injury👌
Same :/
A new meaning to the phrase "My body is ready"
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.
Same buddy
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
That's absolutely astonishing engineering. Crazy that people think an unguided process could produce such a thing. We are wonderfully made!
Evolution is random mutation. You need to understand that to understand human function and physiology
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.
I thought so too :) It's one of those cool consequences of bipedalism
@@Corporis Subscribe and Thanks Sir.
The Nervous system is the system that "just knows." Muscles are merely the slaves of the CNS.
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!
What can you recommend for a locked knee due to a torn meniscus?
Hi Jarel, did you take up the double major? I'm a PT student, biomedical engineering sounds interesting
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
I am an Information Technology student who is also a fan of learning anatomy and physiology. The human body is a work of art.
A work of evolution
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.
Thankyou! By far the best video explaining this!
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.
Dude, this is by far the best Anatomy video I've ever seen. Great teaching methodology
Thanks ....you make it easier to understand
Wow that was fascinating ! It’s the only thing I’ve seen focusing on this little muscle ! I’m fascinated
Thank you, such an amazing video!
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!
Good stuff man you actually tap into how a person actually learns not just coveying information 👌
Thank you! I take pride in my teaching style
Excellent presentation!!! I am a Sports Therapy student at University in UK. These videos are some of the best around.
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!
Great video!
Thank you SO much! this video was very helpful!! :D
Thank you for valuable info👍
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.
Well done.
Your content is always on what i need the most
Are you my guardian angle❤
I'm a medical student and i really love your content. Keep up the great work!
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.
Thanks for your explanation, i'm currently studying for the NPTE and this video help me a lot.
Hi, Nice information
Thanks Corporis, u are very nice.
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 ❤️
Fantastic! I'm a physiotherapy student from the Netherlands, and this video is really helpful for my studies. Thanks a lot!
Thank you, I am a biomechanics instructor and this is the only good video on this topic on UA-cam!
Great video and I am a SPT! Very well done and helpful for understanding difficult anatomy concepts! thank you!
In my last year of PT school, taking the boards soon, and this was helpful-thank you!
i'm a pt trying to learn the terms in corrective exercise course, thanks for the video, it's quite helpful! 🙂
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!
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
Finally 😩some one explain Screw home mechanism for me 🙏 Thanks!
NASM certifed PT. Im fascinated learning everything about the human body. Its truly a work of art!
I'm an SPT who has an exam tomorrow over the lower extremity. You're a godsend!
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.
As a student RMT, this video was very helpful in explaining this mechanism in a simple way. Thank you so much!
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 🌎
I am a first year Physiotherapy student & I love your content! 🇬🇧
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.
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
i ' m physical therapy student and i think i'm totally fall in love with this channel
MRI student! I've watched your videos before, I specifically remember your anatomy and physiology of the kidneys video, which helped a lot! Cheers!
Finally found a video the explains knee locking properly
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 !!!!!!
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
Helpful
Superb👍
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
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
Just a regular athletic/engineering dude who is interested in the anatomy of the human body😍
Love your videos man!
I passed my MBLEx thanks to your channel. Thank you so much!! Keep up the great work!!
I appreciate the kind words, congratulations!
OTS here, this vid helped a lot in understanding what is actually going on here
thank you :)
Great !👏
I am a first year physiotherapy student and this video is so useful for my anatomy exams.
Good clip ; good question. I am a 59 year old violinist (now teaching) who suffered a major stroke 1.5 years ago
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.
MBChB Level I here, found the video quite enlightening
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!!
My pleasure! I actually used to work in a clinic in Phoenix as well during grad school!
Very didadits. 👏🏻👏🏻
much love from a struggling physio student
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.
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
thanks for the explaination! i am a physiotherapy year one student
Happy to help! Best of luck in your studies
I am a pharmacist who loves learning about anatomy, physiology, kinesiology and fitness in general.
My surgeon said I needed to liste loosen the popleteus tendon. It hurts though. Any good videos on this?
2:36 cruciate ligament
PCL tightens and helps glide tibia anterorly during extension
ACL tightens and helps glide tibia posteriorly during flexion
3:52 popliteus: lateral meniscus --> medial posterior tibia
for IR tibia (open chain) / ER femur (close chain)
Tyyyy
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?
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.
谢谢
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.
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.
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
PTA student here!
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?
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.
You should know this stuff already!!!!!! Go to Physiotutors. A little knowledge is enough to hurt people.
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
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 :(.
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 😘
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?
stroke survivor my though i have control i di have knee pain what can i do to relieve the pain/
Greate explanation but why that speed of taking
My right knee locks, when i bend my knee close to thigh. What does that mean anatomically?
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.
Hello - I am a gardener in the west of Scotland, retraining in foot health. Leg and knee anatomy is part of my course. I enjoyed this video, but your delivery is rather fast. If you could slow down and give a few pauses to allow information to sink in, that would be a real help! I'll be back for more, though. Thank you!
Hey
But according to pubmed and grays anatomy in flexion pcl is taut
Can you check this up
Its been a week since the lateral head of my right leg tibia has been constructed and the fracture was closed with the help of a plate. Now i cannot bend the knee. Can anyone suggest me some exercise?
The screw home mechanism is nice but I'm much more fascinated by the "screw you guys I'm going home" mechanism
I LOL'd at this
"Anatomists are boring when it comes to naming things" Are you sure? Have you even heard of the Olecranon Fossa? Of course, YOU have, I mean you're an anatomist. It's just that it's the depression in the humerus that the head of the ulna bone of the elbow goes into when you straighten your arm and yes 'olecranon fossa' literally translates to "elbow head depression" but it's NOT boring!!!
I'm just a guy who has always thought Olecranon Fossa sounded really cool.
Dear Sir i'm from India aged 35, i had medial condyle tibia fracture 2 years ago my hardware removed 1 year ago, i still not walking properly... 1 Daily exercise abou 1and half hour but still not get the idea to do correct exercises please prefer some exercise for proper walking please.
I do squats, quadcurl, romanian bench squat, leg press cycling all these exercises...
All these days i do experiments on all the exercises but for some days they give +ve effects after somedays i think they won't improve my walking...
How months or years are required to proper walking. Or it won't to normal
ACL PLC tighten themselves?
I am a average size jogger who runs 15.2 km per day, 5 or 6 days per week, for several years, now I am 68, and suddenly getting knee issues. I never did warm-ups, so I m sure that's catching up with me. I am learning the various muscles and want to identify the ones I have pain in.
Jogging is really bad for you. No wonder your knees hurt. Slow running kills your knees, hips and ankles. Your muscles are likely the least of your problems.
Just like visiting car mechanics I want to have a little working vocabulary so I don't get flooded and can't advocate for myself for the least invasive procedure. I have a schatzker 3 lateral depression fracture. Osseous rim in tact. @2mm displacement of articular surface. xray tech noted no (apparent) soft tissue damage. We'll see about that popliteus muscle and ACL/PCLs. I happen to have rather hyperextensive knees normally. But even so, good strong trouble free knees. I was a dancer and gymnast and do a regular Vit D dose. After 3 days and major swelling subsided, each day I gently tested and stretched what I could to see what seemed to be working and what was not. bending and flexing was good up to the slight swelling still preventing full folding-but more than 45 degrees and extension stilll a bit shy for the swelling still present. Standing, I did not want to lift my foot to the back. My brain was like, uh, are you sure? It seemed to take twice as much request as should be needed, focus, intent and willingness. All these discouraging me from trying. I moved a small amount compared to the ability to bend my knee in a passive supported motion lying on my back. Going to the osteo in a few days. I am 60, average height and build, working class and need to rehab asap. I do not think the xray images are showing the whole story and knee assessment vids are also telling me more. My leg muscles got twisted as I fell off a low stool reaching up to fix a roll door at a storage facility, but the rubber soles stuck to the surface so I could not adjust my balance and recover. I took a flat, R side of the body fall, legs fully extended, or nearly so in a slight twist as I fell like a tree making a half turn CC from my standing position TIMMM BURRR onto an asphalt surface. My right arm folded under my ribs and cushioned my ribcage and some of the blow. Internal (gracilis?)long connection inner thigh to inside/ medial knee sprained. gastrocnemius medial sore at the base of knee, top of calf 1st few days, then both sides, then traveled downward to base of meaty part. 2.5 weeks later, gastrocnemius still very tender and sore. gracilis or whatever is longest and attached to medial knee solved in about 4 days. No longer tender. Finally went to ER to get a CT scan. They gave me a velcro strapon monstrosity, not even sure it fits right. KILLING my gastrocnemius and one strap snugs down on the top end of the tibia. For real? They wrangled me for over an hour trying to fit it to me. The gastrocnemius hurts more than the fracture. psssh. When I fell, it hurt pretty bad, but I thought insult not injury and tried to stand. NO WAY. The knee gave way under little request or else my wisdom stepped in. Uh, NO. In less than an hour it had swelled to the size of a grapefruit but I could see the compartments staying separated so I figured that was good. Trying to stand (Walk it off Walk it off!) may have caused the displacement, or maybe just the blow that caused the fracture. I iced immediately (and for three days regularly) and elevated for the night. My whole leg ached deeply and I also treated with arnica 200c, Fresh Comfrey compresses, hydrotherapy (hot/cold alternating for a cycle of 3x, 3 x a day) Amino acids and collagen and 3g of curcurmin a day (anti inflammatory). Plus lots of sleeping and rest.
I tell this story in length for all you nerds and geeks who like the forensics of the actions to help with inquiry and to pay attention to not just the gore and glory of broken bones but to the soft tissue damage that can get overlooked in all the excitementbut cause much diversion of healing energy and attention. Hope it helps. Be well, and thanks for the video. Peace.
I’m looking this up for the purpose of my stroke. I can somewhat walk again but cannot unlock my knee due to no control over this muscle and unfortunately I’m not hopeful of ever getting it back.
Interesting, I have lifted weights for about 7 years. 67 yrs old Pretty good shape. I have been diagnosed recently with a slightly torn meniscus. I know there is no cure but I am careful of how I work out now