The sartorius is the longest muscle in the body, but it is best known for allowing us to sit cross-legged. In Latin, “sartor” means tailor. When you combine this Latin word with the notion that tailors sat in a cross-legged position while working, you get the muscle name sartorius. Sometimes, the sartorius is even referred to as the “tailor’s muscle”.
The sartorius originates on the anterior superior iliac spine, which is also known as the ASIS. To find the insertion on a drawing of a human, you should look for the very front-most part of the top of the pelvis.
The insertion is on the upper medial surface of the tibia. This means that the muscle attaches to the inside part of your shin, just below the knee joint.
It is important to note that the sartorius starts toward the outside of your body (at your ASIS) and moves on an inward diagonal path to insert on the inside of your shin, just below the knee. This is important to notice because this path of the muscle will directly impact the type of movements you can do at your hip and knee joints.
Like the rectus femoris, this muscle runs across both the hip and knee joints. This means that it has several functions.
The sartorius has 5 main functions.
- It flexes the hip joint. This means that it helps to lift your thigh in front of your body.
- It laterally rotates the hip joint. Lateral rotation is when you rotate outward. In terms of your leg, when you laterally rotate, your kneecap faces away from the midline of your body.
- It abducts the hip joint. This means that it helps to bring your leg away from the midline of your body.
- It flexes the knee joint. In other words, it helps bend your knee.
- It assists in medial rotation of the tibia (shin bone) on the femur (thigh bone) when the knee is flexed. So, when your knee is bent and you rotate your leg inward so that your knees are facing each other, the sartorius helps.
This muscle is the one primarily responsible for your ability to sit cross-legged. However, it also helps to bring your foot to your leg, as in Tree Pose, and across to the other thigh, like in a Figure 4 stretch.
Injury to the sartorius normally occurs when incorrectly practicing cross-legged yoga poses like Lotus. If you’re trying to force yourself into a cross-legged position or if you’re spending too much time in a cross-legged position, you can end up with pain on the inside of the knee. It’s for this reason that many teachers exercise caution when teaching Lotus, and it’s a great reason for you to be especially mindful of your knees while you practice.
Restoring or Maintaining Health
If you believe you have a sartorius injury, please consult your physician. As with all muscles, the sartorius could tear, so it’s best to seek advice from a medical professional.
However, maybe you simply notice that you have some dysfunction. Perhaps your knees are way up in the air when you sit cross-legged. In order to restore functionality to the sartorius, the best advice is to correctly practice a combination of exercises that both work and stretch it.
For more information, I recommend “Sartorius Muscle” by David Keil. If you have not noticed, I frequently refer to David Keil’s website, www.yoganatomy.com, for information. He does a great job simplifying the sometimes complex activities of the body.
I also consulted The Concise Book of Muscles by Chris Jarmey. Recently, the book was revised and is in its third edition. For some reason, the Amazon link wouldn’t pull up, but I did find the newest edition of the book on Amazon.
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