What does iliacus mean?
The iliacus muscle is one part of what is known as the iliopsoas muscle.
- Iliacus refers to the ilium or ilia, which is the uppermost part of your pelvis.
- Iliacus is one part of the iliopsoas muscle (we’ll cover psoas major next time!).
Where does the iliacus muscle attach?
- One end (proximal) of the iliacus muscle has a broad area of attachment on the inside of the pelvic bowl. You can see it outlined in the image to the right and bottom.
- The other end (distal) attaches onto a bump on the inside and back of the femur called the lesser trochanter. This is the exact same place that the psoas major attaches.
What are the actions of the iliacus muscle?
- The simple answer is that the iliacus muscle flexes and externally rotates the femur.
- When combined with the psoas muscle, the two muscles are considered the strongest hip flexors in the body.
- It uses the pubic bone as leverage to create some of that strength.
- The iliacus muscle can also add to an anterior tilt of the pelvis (down and forward).
Keep in mind that most muscles are described from anatomical position. This means that it is assumed that the pelvis is more stable than the femur, which is true most of the time. However, things are not so simple in the body. Not only could we find ourselves lying on the floor and using this muscle to lift our pelvis, torso, and spine, but we would also use this muscle to help stabilize the femur and the pelvis relative to one another.
Postures where this muscle contracts
This muscle contracts in boat pose.
Although she is using her hand to help, this muscle contracts along with other hip flexors in utthita hasta padangusthasana, and helps lift the leg and to keep it up.
This muscle contracts and should be used to bring you into a forward bend.
Postures where this muscle is lengthened
Supta virasana lengthens this muscle. You can put more pressure on it by lifting the hips in this position as well.
This muscle lengthens when the hip joint goes into extension, especially if the knees stay straight.
Ustrasana (below) also lengthens this muscle when the hip moves into extension.
Iliacus muscle injury
Iliopsoas tendinitis: This means that the muscle is generally sore/tender, as with tendinitis of any muscle. It’s caused by overuse of these two muscles, iliacus and psoas major, usually from a sport (e.g. running and/or bicycling)
Iliacus dysfunction: The iliacus muscle is in a constant state of contraction from long periods of keeping the muscle in a shortened position (i.e. lots of sitting, driving, etc.). This can create trigger points and refer pain to a number of locations in the lower body. (See below for the image of trigger points from the iliopsoas)
You may also recall an article I wrote related to a “pinching sensation” near the inside of our hip when adducting the thigh as we do in twists. This is usually the iliacus muscle. Check out the video on the article to see how test and see if it is your iliacus.