While it may sound like an astrological star sign, the sartorius actually the longest muscle in your body, stretching from the anterior superior iliac spine (ASIS) to the medial knee. Named from the Latin sartor ‘tailor’, (commonly thought to have attained this name in reference to the activation of the muscle when sitting in the cross-legged position once adopted by tailors). It also is a bi-articular muscle, meaning it operates on two joints, the hip and the knee.

The sartorius is the longest muscle in the body, connecting from the front of the pelvis to the inside of the knee.

Like Cinderella, the sartorius is often overshadowed by its more famous “step-sisters” − the psoas and iliacus − as a cause of anterior hip pain. Yet an overly tight sartorius can cause acute discomfort at the front of the pelvis. Like the iliopsoas, it can also adaptively shorten due to sitting, which results in chronic dysfunction. This dysfunction can have concomitant far-reaching effects throughout the body. For example, considering the downward pull of the sartorius on the ASIS, chronic tightness in this muscle has the potential to cause stress and impingement in the lumbar spine.

At the hip, the sartorius acts in synergy with the iliopsoas for hip flexion and aids the lateral rotators (gluteus maximus, obturators internus and externus, gemelli superior and inferior, quadratus femoris and piriformis) to create hip external rotation. Along with the tensor fascia latae, gluteus maximus and gluteus medius, sartorius abducts the hip. At the tibiofemoral joint, the sartorius is a synergist in knee flexion (working with the prime movers – biceps femoris, semitendinosus, and semimembranosus) and involved in medial rotation of the flexed knee. The next time you look at the sole of your shoe to see if you have stepped in gum, give a shout out to your sartorius (and it’s back up band), which is orchestrating all these directions of movement simultaneously!

Because it crosses at the knee, the sartorius can also be a cause of medial knee pain. Joining with the tendons of gracilis and semitendinosus to form the pes anserinus (PA) tendon, tightnessdysfunctional movement patterns and over use of any of these muscles can result in inflammation at the PA tendon, and sometimes its under-lying bursae. This inflammation may be experienced as pain or hypersensitivity on the inside of the knee[1].

Other symptoms of sartorius-related muscle pain can include a burning or stinging sensation at the front of the hip. This pain may be brought on by an overt trauma, such as an athletic injury. Sports which require sharp turns around a planted foot, such as basketball and football, or a fall whilst skiing where one foot remains trapped in deep snow, can expose the sartorius to unexpected and sudden torsional forces resulting in muscle strain and tissue damage.

Outside of acute injury, however, poor postural and alignment habits can also contribute to sartorius-related pain. Now that you’ve read this introduction to sartorius anatomy, check back in on Friday to read more on how our habits may be contributing to sartorius dysfunction and how Yoga Tune Up® can provide relief!

[1] Rennie, W.J. & Saifuddin, A. Pes Anserine Bursitis: incidence in symptomatic knees & clinical presentation. Skeletal Radiol (2005) 34:395-398


Enjoyed this article? Read Hip Space Available Immediately: A Step on the Path to a Balanced Pelvis

Ali Bell

Ali was introduced to yoga by a roommate over 10 years ago – who obviously thought she needed it. As someone who biked all winter and ran and swam all summer, yoga became a bit of a life saver in terms of providing some physical and mental flexibility. Over the years yoga quickly began to surpass her interest in other pursuits – and some may say that is because the Scottish person in her truly appreciates how much cheaper yoga is than fancy running shoes. Since graduating from a 200 hour yoga teacher training program in 2007 (Bodhi Tree Yoga, Regina, Saskatchewan, Canada) Ali has continued on as a committed yoga teacher with an active physical practice and a keen interest in the anatomy and physiology of movement. Having been a keen follower of Jill Miller and Yoga Tune Up® since starting her journey as a yoga teacher, Ali completed the Level 1 YTU Training in October 2015. With a full-time day job as a Research Scientist for a local regional health authority, Ali continues to teach yoga part-time, infusing her classes with the science of movement and guiding people to be researchers of their own body.

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Alison Quinn

Great post! I was really wondering about the role of the sartorius and this was a great in-depth introduction. I also experience hip “stuff” sometimes and maybe my sartorius is to blame – worth thinking about! Great timing

Amber Green

Thank you for this article! I never thought of the Sartorius being a problem. I experience pain at the front of the hip and the medial side of the knee as well as sore glutes and piriformis, and ql. I always attributed these symptoms to a problem with the psoas as it is often associated with back and knee pain. Many of the figure skaters I teach have these sensitivities as well and this will be information that may help some of them relieve some of their pain.

Catherine RL

Thank you for this article. Very informative and I am absolutely fascinated. The more I read, the more I want to read and learn.

Tammy abresch

Sartorius muscle can certainly cause a little confusion. As a new Yoga Tune Up student feeling a little overwhelmed I sure have enjoyed this article. Thank you


Thank you for this article. I didn’t give much thought to the Sartorius other than the fact it was the longest muscle in the body. This has helped me to better understand my own medial knee pain in my right knee from running a marathon several years ago. I am on a quest to figure out what happened and why to my knee. This is very interesting and I will now have to pay more attention to the Sartorius.


A very interesting post, thoughtful and detailed, about the “unsung” sartorius. Thanks for shining a light on it!


I didn’t know anything about the sartorius and this post was very detailed and helpful in a relatable way.
I know a lot of people who do not wish to exercise due to knee pain, but helping them understand it may be a tight sartorius or other related issue is helpful and encouraging.

Wendy Hensley

Very good article. So much detail and I took lots of notes. Thank you.

Dejia B.

Wow, this was super illuminating! I’ve been having burning pain on the outside of my hip and front side of my hip (along with lumbar pain) for the last few days which I was convinced was my psoas, but after reading this…..not so sure anymore! I’ll be exploring more within my own body to see if I can further deduce, but this article gave me some great new ideas. Thank you!!


I realy like your comparaison with Cinderella. It’s true, we always thinking about
others mucles before him. It’s more important for the hip then we think. Thank you.

Janie Donais

Wow!! Loved this article!! This will help me so much in understanding lots of hip movements!!


Ali, thank you for this post! I’m delighted by your Cinderella reference- and it’s spot on! I can’t believe how much I didn’t know about this very important muscle. I recently gave my Sartorius muscles some love with the YTU therapy balls and it was incredibly therapeutic. Now I have much better context as to how the Sartorius works and why proper care of it is essential.

Noelle Carvey

Loved this! Pretty sure this is the one pulling on my right side! I enjoyed the thorough information, and was even more excited that it all made sense! I remember this one because of its beauty and multi purpose ability! When I’m walking, sometimes I get that twinge, burn sensation in that Asis region. I’m focusing on re alignment of this whole body! Haha.

Jenni Everard

What an amazing muscle that does so much! So much excellent information. Thanks!


I forgot that the Sartorius connects at the hip and at the knee. I found this blog to be very informative and love how the reader gets a full sense of what this muscle does. I like how all the information is laid out.


I have a peculiar (and chronic at this point) painful pinch when I flex and horizontally abduct my right hip. Looking at the attachment point of the Sartorius, I wonder if it may be contributing to or directly responsible for the pain, as the pain feels high up in the hip crease and quite superficial.


Ironic how the longest muscle in our body is so overlooked. The fact that it crosses over two joints makes it even more significant to our lower limbs (for injury prevention and for pain relief). Thanks for sharing.

Ashley Everhart

Funny! Thanks for sharing that in a a memorable way. I had some crazy knee instability recently and I think it was related to this and perhaps those step sisters as well! Thanks for the blog!

Stefanie Eris

You’re absolutely right to say this is the Cinderella muscle! Thank you for bringing this important muscle into the light, and for so clearly articulating its actions in all directions of movement. Super clear and useful.

Laurel Crane

Found this article very informative. I definitely focus more on the psoas and illiacus more than sartorius. I have recently been experiencing inner knee pain and I’m now going to delve deeper into caring for my sartorius to see if I experience change.

Natalie K.

I love this article. The Sartorious muscle is often overlooked, the fact that it crosses two joints and is the longest muscle of the body should make this muscle a star. Thank you so much for sharing.


Great Article. The sartorius is so often overlooked, what an important muscle. I didn’t know it was the longest muscle and it crosses two joints.


Will be reading your next article. I have a difficult issue in my right hip sitting in Sukhasana. I suspect that the sartorius is part (only part) of the issue. I am right side dominant, could that contribute to that muscle being tighter?


Thank you for addressing a muscle not frequently talked about. I had no idea it was the longest and that so many activities can affect it.

Donna Burch

I love this blog! Yes, it does sound like an astrological star sign. I never thought of that.
You made me laugh out loud and want to read all your other blogs. Thank you!


Thanks for sharing, Ali. I know of someone who will be blessed by this knowledge as I help him with his leg and knee pain. Looking forward to applying what I know!


This is a great overview of the Sartorius and what it does. It’s always good to learn about what can cause knee pain. And knowing that poor posture can lead to Sartorius pain is just another reason to do invest time in YTU. I also like the “Cinderella” analogy.

Claudia Muehlenweg

This is so enlightening and helpful since you told the whole story of this muscle versus the pieces we find in our anatomy books. And i liked that you gave a lot of real life examples of how one could injure it. That helped me a lot to embody it. I also wonder if the cause for my often sensitive and slightly painful (in low lunges) medial knee area is a strained sartorius?

Genea Crum

Great information! Another possible answer and solution to chronic knee issues. I also love that you added the explanation of how the muscle was named (tailors sitting with legs crossed).

Rachel T.

I love this metaphor of Cinderella and her step sisters. As a person with knee pain I will certainly be looking to the hip and the sartorius as a potential blind spot! Thanks for the insight 🙂

Juliana Attilio

This was a great synopsis of the often overlooked sartorius. I had learned about how great it was 15 years ago in massage school, but had really only remembered how it was the muscle that allowed us to cross our legs like a tailor. It’s great to be reminded of all the things sartorius does and to keep it on the radar when assessing hip and knee dysfunction.

Adriana Robertson

Great to learn more about sartorius. I’ve been told that it’s likely the cause of some knee and hip pain but hadn’t ever really understood what its role was. I’m curious to learn more about how posture and alignment habits can affect this. Thanks!

Diana Germain

Thank you, this is a muscle I am going to pay more attention to as well as I continue to work on strengthening and bringing greater stability and balance into my hips. In particular, I need to pay attention to strengthening these muscles because I have a labral tear that now requires surgery. I’m pretty sure it came about in the first place in part from dysfunction and imbalance in this area.

Jen Wheaton

What a great analogy to describe the role and function of the sartorius! I have a student who has been articulating having a burning sensation in his left hip, and your article has spiked my curiosity into how to help him target the sartorius in his practice. Thank you for your insight!


This article has piqued my interest–looking for more info on working on the sartorius for my students, most of whom are CrossFitters.

Amy Moore

I have been working through some anterior hip discomfort and until I read this post I hadn’t considered the sartorius as a possible culprit. I also deal with medial knee issues occasionally. I am excited about this new info and where it might lead. Thanks for sharing your knowledge.

V. Ceglarek


As a beginner student of anatomy, I really appreciated the emphasis you put on synergy and relationships among the muscles. The Cinderella analogy is brilliant.

Thank you.

Gretchen Corbin

thanks for the informative and fun-to-read blog post. I’ve been dealing with some anterior hip pain and was focusing on my illiacus & psoas. You have reminded me that I need to look beyond those “step sisters” to other surrounding muscles too. Thanks for the timely post!

Lisa Pitel-Killah

This is a great read. It is funny how we look to the big movers first thinking that they are the issue but really when a muscle crosses 2 joints it can definitely be the problem. Being new to anatomy and learning quickly this reference will definitely help me not to overlook the power of the Sartorius.


Any suggested solutions?

Sue Kilpatrick

Ali, great blog. So informative and the timing is perfect for me as I am taking the Anatomy workshop with Alex this weekend. I love your “Cinderella” reference. It is something that is unique and will help me and other anatomy newbies remember the Sartorius.

Erin Hoien

Very eye opening. So many actions and so many ways it could get overlooked as the culprit in hip and knee pain. This muscle’s been on my mind lately, mostly b/c mine lacks range of motion. When I began considering that, and some of my discomfort in my hips and knees- I started to consider the ‘Cinderella’ muscle. This is very timely, looking forward to more.

Shari Williams

Very interesting how many functions this skinny long muscle performs. It makes perfect sense now that you made me think about it, it is biarticular, therefore affects the movement function in 2 joints, a lot more to go wrong when imbalances occur from trauma or repetitive shortening as in sitting. And i never knew what a PA tendon was. Now I kind of do!

Gabriela Rodríguez

Thanks for your post Ali, I love reading and knowing more about “Cinderella muscles” as you precisely said. There were a lot of things in your post that opened my eyes and inspired me to explore more about Sartorious and “treat” it on my classes. By the way, I am teaching a Hips Workshop next months so this post came on at the right time for me. I will look into more articles by you as I founded your way of writing and explaining very understandable and amicable!

Tonia Briones

Well written article. So Clear and well laid out… it felly reading a story. I was delighted of the analogy of seeing Sartorius and Psoas made twin sisters and sartorius being overshadowed by Psoas sister! I will remember all these points when teaching Tune up classes. Thank you so much.


Great info Ali. Thank you! When I extend and abduct my legs, I always feel a little slippage around my medial knee. I think I’ve found the culprit. Never painful but bothersome because I feel like I could strengthen at one end or the other to
Correct. Will look forward to next week’s info with Yoga Tune-Up balls at the ready.
Thanks again!

Casey Thomas

Thank you, Ali! Good to know more about one of the key players in hip flexion and external rotation!

sarah howard

Hey Ali! Nice post! I have been working on learning different muscles (taking the YTU level 1 cert now) and the Sartorius is one that keeps slipping my mind. I LOVED how you talked about the latin root sartor, or “tailor”. It gives me a great visual of the activation of that muscle when the leg is crossed.

I work with athletes and it is important for me to really know the muscles that cross the knee (like this one). Anyways, thanks again for such a clearly written post!

Simran Khalsa

Thank you for this article, I’m learning, more in-depth then I have before, about all the various muscles what they do and when used incorrectly the resulting problems, I look forward to your article on how Yoga Tune Up can provide relief.

Becky Battle

I like your description of this muscle that is often forgotten and the mean “step-sisters” get all the credit for dysfunction and pain. Let’s not forget all the contributors to dysfunction and pain. It’s so fun to do the detective work and find out the real issue. Good anatomy review.