The psoas minor is a fairly modest-sized muscle that lies on the front side of the larger psoas major muscle. It acts as a weak flexor of the trunk, helping a person bend forward.

The psoas minor originates via attachment to the T12 and L1 vertebrae, in the mid-to-low back. This refers to the thoracic and lumbar spine and the intervertebral disc between them. It then travels down and attaches to the iliopubic eminence (the junction of the pubis with the ilium on the front side of the pelvis) with a long tendon.

The nerve that controls the psoas minor is the anterior primary rami of L1.

Oddly enough, about 50 percent of people don't have a psoas minor muscle. Someone that has the muscle and strains it, however, can experience a 50 percent reduction in range of hip motion.