A Minor Issue?
Only about half of people have a psoas minor muscle—does it matter?
When you work with enough clients, eventually you notice all the variations in biomechanics and anatomy. You may or may not remember from your fitness professional certification studies that only about half of people have a psoas minor muscle. When it's there, it lies in front of the psoas major and originates from the sides of the 12th thoracic vertebra (T12), the first lumbar vertebra (L1) and the corresponding intervertebral disk (Farias et al. 2012).
It is a "weak trunk flexor" that, if present and strained, can reduce range of motion in the hip by as much as 50% (Healthline 2015). However, if you don't have a psoas minor, are you at a disadvantage?
"In almost 30 years I have not seen research or clinical indications that it matters," says Christina M. Christie, PT, president of Pelvic Solutions LLC, in Park Ridge, Illinois. "For the most part, the great majority of the population have tight hip flexors and a tight anterior chain, because we are a population that sits from the time we enter preschool. So no, it doesn't matter, because not one muscle in our bodies functions in isolation. The brain does not know muscles; the brain knows movement patterns."
Each issue, this new column will highlight an unusual or esoteric fact about the body, along with clear, expert advice about its relevance to fitness professionals. If you'd like to share a fun fact about anatomy, biomechanics or one of the body's main systems, contact IDEA executive editor Joy Keller, [email protected]
References
Farias, M.C.G., et al. 2012. Morphological and morphometric analysis of psoas minor muscle in cadavers. Journal of Morphological Science, 29 (4), 202-205.
Healthline. 2015. Psoas minor. Accessed Nov. 14, 2016. www.healthline.com/human-body-maps/psoas-mino.
Joy Keller
Joy Keller is the director of marketing communications & PR at IDEA, and has also served as executive editor of IDEA Fitness Journal, IDEA Fitness Manager, IDEA Pilates Today, and IDEA Fit Business Success. She is also a certified personal trainer, indoor cycling instructor and yoga teacher (RYT 200).