Psoas Muscle Origin and Insertion: A Plain Guide

The psoas muscle origin and insertion are easy to state: psoas major starts along the sides of your lower spine and ends high on the inner thigh bone, so it links your back to your leg. As a teacher of the Feldenkrais Method®, I like anatomy that you can feel in your own body, so this guide keeps the Latin short and says what each part means in daily life.

Psoas muscle origin and insertion: the short map

A muscle has two ends. The origin is the end that is usually steadier, and the insertion is the end that usually moves more. For the psoas, the spine end is the origin and the thigh end is the insertion. In real movement, either end can be the one that moves.

Here is the map for psoas major:

• Origin. The sides of the vertebral bodies (the thick, round front parts of the spine bones) from the last chest vertebra, called T12, down to the fourth or fifth lumbar vertebra. It also starts from the discs between them, and from the transverse processes of L1 to L5. Those are the small bony wings that stick out sideways from each lumbar bone.
• Insertion. The lesser trochanter, a small knob on the inner, upper part of the thigh bone (femur). Psoas major joins the iliacus muscle here, which comes from the inside of the pelvic bowl. Together they are called the iliopsoas.

That is a long origin and a short, strong insertion. Picture a rope fastened along the side of your lower spine, passing forward over the pelvis, and tied to the top of the thigh.

Where is the psoas muscle located in the body?

The psoas lies deeper than most muscles you know. It sits along the sides of the lumbar spine, behind the organs of the belly, such as the intestines and kidneys. From there it runs down and forward, passes over the rim of the pelvis, and crosses in front of the hip joint on its way to the thigh.

This is why people struggle to point to it. Your hand can touch the front of the hip, but the muscle itself is several layers back. Some bodyworkers press through the belly to reach it, yet what they feel is still debated, and a firm press there is not for everyone. I would not try to find it with your thumb. Sensing how the hip and back move tells you more.

The nerve supply comes from the lumbar plexus, a network of nerves that leaves the lower spine, mostly from the L1 to L3 levels. You do not need to remember that, but it shows how closely this muscle is tied to the lower back.

Psoas minor: the muscle many people do not have

There is a second, smaller muscle in the family. The psoas minor lies in front of psoas major. It starts on the sides of T12 and L1 and ends on the pelvis, at a ridge called the pectineal line and a bump called the iliopubic eminence.

Many people do not have one. Common anatomy texts suggest it is missing in roughly 40 to 60 percent of people, though studies vary. If you do have it, it is slim and adds little force. Not having it does not appear to matter, which is a good reminder that bodies differ and that this is normal.

What the psoas does: psoas major muscle function

The clearest job is hip flexion: bringing the thigh toward the trunk, or the trunk toward the thigh. You use it when you lift a knee to climb a step, swing a leg forward in a walk, or sit up from lying down.

Its role in the spine is less settled. Because it attaches along the lumbar bones, it may help steady the spine, bend it a little to the side, or tilt the pelvis. Researchers and teachers disagree about how much it does each of these, and it probably depends on position and task. Anyone who tells you it does one single thing is simplifying.

Low back trouble is common. About 619 million people were living with it worldwide in 2020, according to the World Health Organization (WHO, 2023). With so many muscles in that region, it helps to see the psoas as one member of a team, not a lone suspect. Our guide to what causes a tight psoas muscle looks at that team in more detail.

A Feldenkrais® angle: the hip joint and low back share the work

In a Feldenkrais lesson, I rarely ask people to find one muscle. I ask them to notice how the whole area takes part. Here is a small experiment to try, only if it feels comfortable.

Lie down face up, knees bent, soles resting on the floor. Slowly let one knee drift toward your chest, then lower it. Where do you feel the movement start? Is it in the front of the hip, or does your lower back also shift? Does your pelvis rock a little? Do it again at half the size and half the speed. Rest and compare the two sides.

Many people find that the hip joint and the lower back trade the job between them, and that a large, quick lift feels different from a small, slow one. You can also roll your pelvis a little toward your ribs and back again, and notice what your belly and breath do. None of this has a right answer. You are building a clearer picture of how you move. Our somatic exercises for beginners page offers more gentle ways to practise this kind of sensing, and the Feldypedia article on hip stiffness and limited mobility puts it in a wider context.

Why psoas muscle origin and insertion matter in daily life

Knowing the two ends helps explain what you may feel. Because the psoas starts on the spine and ends on the thigh, a long day in a chair keeps those two ends close together. Standing up afterward, some people feel a pull at the front of the hip or a deep ache low in the back. That does not mean the muscle is damaged. It often just means you have been in one shape for a while.

If you want to look at what pain in this area can feel like, read our guide on psoas muscle pain. For a gentle approach to the muscle itself, see how to release the psoas.

Feldy teaches this kind of sensing in brief audio lessons made for home, and the 7 day free trial lets you see how it feels. The body awareness program shows how those lessons are shaped.

Alongside clinical care and other methods

Learning like this goes hand in hand with care from your doctor or physiotherapist, and never stands in for it. Deep pain in the groin, hip or low back has many possible sources, and a clinician can find out which one applies to you.

Other movement methods are different options with a different mechanism. Pilates and strength training build control and effort in chosen muscles. Yoga explores range and flexibility. Plenty of people mix several of these. A Feldenkrais approach brings a calm way to sense how the hip, pelvis and back cooperate.

Common Questions about the psoas muscle (FAQ)

Is it safe to explore my psoas through movement?

Slow, small movements are usually well tolerated. Keep the effort low and stop if anything turns sharp. Take extra care with a diagnosed hip or spine condition, recent surgery, or pregnancy, and ask your clinician first. Get urgent help if a leg goes numb or weak, or if you lose control of your bladder or bowels.

How often can I practise sensing my hips and low back?

A few minutes most days works well. The movements are small and gentle, so you do not need rest days between them. Short pauses during the day, where you simply notice how your hips and back move, add up too.

How long until my hips feel different?

Some people notice an easier lift of the knee within a single session, though it may fade by evening. More lasting change tends to come with several weeks of gentle, regular practice. If you notice no shift after that time, talk to a clinician.

How is learning about the psoas different from stretching or strength work?

Stretching works on range, and strength training builds effort in chosen muscles. Many people enjoy both. A Feldenkrais approach is a different mechanism. You move slowly and sense how the hip joint, pelvis and lower back share a movement, instead of aiming at one muscle.

When is it time to see a doctor about hip or groin pain?

Make an appointment if the pain started after a fall, grows steadily, disturbs your sleep, or arrives with a fever or weight loss you cannot explain. A numb or weak leg, or any trouble with bladder or bowel control, needs urgent care. A doctor or physiotherapist can find the real source of deep pain.

Where is the psoas muscle located?

It lies deep inside the body. It runs from the sides of your lower spine, down through the belly behind the abdominal organs, across the front of the pelvis and into the top of the thigh. You cannot easily touch it from the outside.

Does everyone have a psoas minor?

No. Many people do not have one, and common anatomy texts put its absence at roughly 40 to 60 percent of people. When present, it is a slim muscle lying in front of psoas major and ending on the pelvis. Missing it does not seem to cause problems.