Anatomic Diagram Correction on Largest Low Back Muscle- Psoas

Too often, anatomic diagrams are incorrect in their description of muscles and how they are drawn.

A 6/23/2015 facebook post to my professional facebook profile:

https://www.facebook.com/pages/Dr-Mark-Saracino/67386593584?ref=mf

…from a dancer and choreographer in Detroit had a diagram of the largest low back muscle which is deep inside the front of the spine behind the belly-button. My response to the incorrect post is as follows.

Pronounced “SO-iss” it is the primary thigh flexor muscle which is contrary to what most people think flexes the thigh forward- the large front-of-thigh muscle rectus femorus. Most folks over-work the psoas by performing abdominal exercises incorrectly. Flexing the leg onto the hip overworks the psoas, which also increases the curve in the low back, so instead of it decreasing low back pain leg-lifts and the like increases low back pain! The best way to exercise the abdominal muscles is to flex the rib cage onto the pelvis while exhaling WITHOUT flexing the thigh onto the hip, with cable-pull down techniques which I can demonstrate in the office.