Dooley Noted: 12/17/2014
Everybody on the planet seems to know where the psoas muscle group is located.
And if one knows psoas, he most likely is stretching it.
Imagining people stretching the psoas makes me cringe – mostly because this muscle falls apart in my hands during dissection.
At this point, I’ve visualized and helped dissect around 850 of them bilaterally.
To eccentrically load (stretch) this muscle, you have to involve many players that may not appreciate the pull you’re exerting.
The psoas major attaches to the intervertebral discs, starting below the last thoracic vertebrae and extending to the fifth lumbar vertebrae. It just misses the lumbosacral disc, an area susceptible to disc herniation.
Along with the discs, psoas is largely adherent to the bulky anterior bodies and transverse processes of these vertebrae.
Superiorly, the diaphragm’s medial arcuate ligament connects to psoas. Medially, the psoas fibers are nearly indiscernible from the diaphragm’s crura (read: legs).
So, every time you breathe, psoas and diaphragm work together to provide anterior spinal stability.
During development, psoas formed around important lumbar nerves. In dissection, these nerves are imbedded within psoas, so much so that one cannot fully see the nerve sources until psoas is resected.
These nerves supply important muscles in the thigh, as well as cutaneous nerves covering immense surface area in the anterior abdomen, thigh, groin, and even the scrotum and labia majora. Even your autonomic nervous system runs directly deep and medial to psoas.
The fascia covering psoas covers the kidney, as well as the nearby quadratus lumborum muscle.
That’s why a “psoas sign” (read: hip flexion) exacerbates kidney pain, when present.
The psoas major is not quite done, since it joins up with another hip flexor and external rotator called iliacus. These two have different innervations but share an insertion on the femur.
The psoas crosses many joints. Iliacus doesn’t. Iliacus also doesn’t have nerves running through his belly, and he doesn’t stabilize the spine.
If your low back hurts and your hip flexors (front pockets) feel tight, stretching the psoas may not be right for you.
This is particularly true if you have difficulty pulling your anterior ribs towards your hips. This anterior rib cage tilting is crucial to the diaphragm contracting directly inferiorly and not at an oblique angle.
This presentation tends to happen in people with a tight diaphragm.
Stretch the adjacent structures – not the psoas!
If the hips are tight from a forward pelvic tilt, psoas is not the one to stretch. Imagine putting nerve tension on all those structures passing through psoas!
Stabilize the spine and move through the hip.
Free up the ribcage so the diaphragm can properly move.
Lay off psoas and focus on adjacent anatomy.
As always, it’s your call.
– Dr. Kathy Dooley