The Psoas Muscle And Iliacus Are Part Of The Core

The Psoas Muscle

David Keil Anatomy, Torso 3 Comments

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What Does Psoas Muscle Mean?

The Psoas Muscle

  • Psoas literally means “muscle of loin” (Greek).
  • Three muscles are associated with what is commonly refered to as “the psoas”: the psoas major, psoas minor, and iliacus.
  • The psoas major is the larger of the two psoas muscles.
  • The psoas minor is the smaller of the two psoas muscles and is absent in approximately half the human population.

Where Does the Psoas Muscle Attach?

  • The psoas major’s proximal (closest to the head) attachment is on the sides of the bodies of the vertebrae from T12 through L4. It continues down the sides of the spine, over the front of the pubic bone, and then attaches at the distal end, with the fibers of the iliacus, to the lesser trochanter of the femur.
  • The psoas major crosses many joints: T12–L1, L1–L2, L2–L3, L3–L4, L4–L5, L5 – sacrum, sacrum–ilium (SI joint), pubic symphysis, and the hip joint.
  • The iliopsoas connects the upper half of the body to the lower half of the body.The Psoas Muscle Attachments

What Are the Actions of the Psoas Muscle?

  • The iliacus and psoas major are generally grouped together as the “iliopsoas” when referring to the function of either individual muscle.  The primary function of the iliopoas is to flex the hip joint.
  • Secondarily, the iliopsoas externally rotates the hip joint.
  • It can also be involved with adduction of the hip if the hip has already been abducted or taken out to the side.
  • Because of its location, the psoas muscle is ALWAYS associated with the “core” of our body.
  • It directly impacts the quality and lightness of our movement because of its relationship to our center of gravity. See my old article on the psoas for more details of moving from your center.

Postures Where the Psoas Muscle Contracts

psoas muscle in kurmasana

Kurmasana requires the psoas muscle to contract.

psoas in upavishta konasana

Upavishta konasana requires psoas as well.

psoas in navasana

Navasana is not just about the abdominals. Deep to the abdominals, the psoas is contracting strongly.

Postures Where the Psoas Muscle is Lengthened

psoas muscle in dhanurasana

Dhanurasana stretches the psoas muscle.

psoas muscle in supta virasana

Virasana not only stretches the quadriceps, but the psoas too.

psoas muscle in pigeon pose

In the back leg of this posture, the psoas is getting stretched.

Psoas Muscle Injury

Psoas syndrome/overuse:

Psoas, like the iliacus, can become sore from repetitive use/stress, either from daily activities like long periods of sitting, or through a sport like running or cycling.

Pain can be felt directly at the iliopsoas when sitting for long periods, for example, when driving a car for a long distance. Pain can also refer to other areas of the body, like the lower back.

Resting the muscle by taking a break from your activity can help alleviate acute pain. Due to where the psoas is located deep in the body, a skilled professional body worker may be needed to treat psoas syndrome/overuse.

Psoas strain or tear:

If psoas overuse is accompanied by a certain amount of force, it can result in an actual tear in the psoas. Psoas tears can be grades 1, 2, or 3
Grade 1: small tear, some pain, full function of the muscle
Grade 2: larger tear, some loss of muscle function
Grade 3: most muscle fibers torn, major loss of muscle function

Trigger Points

Trigger Points in the Iliopsoas Muscles

Additional Images


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This website is simply about delivering yoga anatomy to the yoga community in a simple and understandable way. It has always been about you, the reader, understanding the complexity and diversity of our own humanness as well as our anatomy.

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  1. Pingback: Psoas: Learn Your Muscles - Custom Pilates and Yoga

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