Three hip flexors: Iliopsoas, Sartorius and Rectus Femoris


Three hip flexors: Iliopsoas, Sartorius and Rectus Femoris

Flexion (drawing the legs towards the trunk or making your bicep pop, for example) is a primary piece of our fear response and human beings are a terrified bunch. This fear manifests in the pelvis through a chronic shortening or engagement of muscles and keeps us stuck in a state of constant alarm. Our body flexes and extends and rotates and we are forever searching for balance in the front, back and sides of the body to allow for these movements to be successful.  The search is all too often in vain.

One common place of imbalance is the hip flexors— yesterday’s post was Your Poor Quadriceps, about one of these muscles but well the same goes for the others as well. The hip flexors of the title are the three muscular options for bringing the leg closer to the trunk. With good posture and movement patterns they all work together endlessly in the course of your day.

Sartorius is the longest muscle in the body and I’m sure that I am being naive when I call it fairly inconsequential.  It begins on the upper rim of the pelvis crossing the thigh to attach on the inside of the knee. Long and thin it gets a functional assist from the femur bone with which it articulates. In addition to its role as a hip flexor, the sartorius abducts (pulls away) and laterally rotates the hip, and helps with knee flexion.  Picking up your foot to look at the bottom of your shoe displays the sartorius in action.

Of the three hip flexors Psoas major is the strongest and the only one that connects to the spine. Iliospas is the meeting of the psoas major muscle and the iliacus. The iliacus lines the wall of the pelvis before forming a common tendon with the psoas major to connect at the lesser trochanter, a small bump of bone on the back half of the inner thigh. The psoas major connects along the lower spine. We think the psoas is the most important muscle in the body—it holds us up, walks us through life, and warehouses the trauma we can’t deal with in the moment.

Rectus femoris is one of the four quadriceps muscles and though it is a hip flexor, poor postural alignment renders it moot in my book (the same goes for psoas and Sartorius for that matter). All four of the quadriceps meet to form the patella tendon connecting to the shin below the knee. Rectus femoris connects to the pelvis which makes it a hip flexor while the other three muscles of the quadriceps (the vastus), acts to stabilize the knee in extension.

Healing comes with knowledge and the more you know about your body and the way it works, the easier and more likely it will be to change patterns that might have been hindering you your whole life. The hip flexors can hold you back or make your motor hum. Good posture and happy hip flexors allow for a body that welcomes the fear response only to process it and let it go.

If you found this post to be helpful, you might be interested in my Psoas Release Party! video set.

For a limited time we are offering my Psoas Release Party! video on sale at a specially discounted price. The Psoas Release Party! can both explain your issues and help you get out of pain by letting go of long held tension with relative ease.

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Saturday Morning Musical: James Cagney
Your Poor Quadriceps Muscles
15 Comments
  1. Sartorius is an important muscle, not inconsequential, in my view, but then, I’m a ballet teacher, and we use it a lot….there are several basic positions in ballet that demand a highly functioning sartorius muscle. For example a “passe” or “retire” position where the toe of one foot is pointed at the knee of the other (standing) leg, with the knee turned out to the side. Thus the flexion, outward rotation and abduction capabilities of the sartorius are all on display. And there are others….

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  3. You say the sartorius attaches to the outside of the knee, but the illustration shows it attaching to the inside, Just wondering if this is a typo, I only ask because this is where I had knee pain until I started using better alignment and shoes.

    • You are correct. It is part of the Pes Anserine or “goose foot” that all attach on the medial side of the knee. The Pes Anserine is comprised of the Gracilis, the Semitendonosis, and the Sartorius

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