The Psoas Major: Part 1

The psoas major, the body’s main engine of walking, is one of three muscles that make up the iliopsoas muscle group. The psoas major inserts on the back half of the inner thigh, comes forward to cross over the rim of the pelvis and moves backwards again to attach along the lumbar or lower spine. The iliacus muscle lines the inside wall of the pelvis and joins psoas major to form a common tendon inserting together on the back half of the inner thigh. Psoas minor is an interesting muscle that anatomy books will tell you it is present in only 50% of people and is slowly disappearing. Though this is technically true the body has many different connections, one of them being through fascia, a connective tissue that we will go into in future articles. So even if you don’t have this muscle it is likely to manifest energetically through the fascial lines of the body. Bodyworkers often refer to feeling this muscle whether it is there or not.

Psoas major attaches at six points, the back of the inner thigh and then five different points along the spine. The first four vertebrae of the lumbar spine, which is the lower back, and the bottom vertebrae of the thoracic spine; which is anything that includes a rib. (T12). As a result the psoas spans and affects many joints as opposed to the iliacus, for example, which only crosses the one joint where the leg meets the pelvis.

The psoas is unique for many reasons and over the course of posting we will cover all of them.