Origin: Side of T12+L1 and IV Disc between
Insertion: Pectineal line and iliopectineal eminence
Action: Weak trunk flexor
Antagonist: Gluteus maximus
The Psoas minor (Psoas parvus) is a long slender muscle, placed in front of the Psoas major. It arises from the sides of the bodies of the twelfth thoracic and first lumbar vertebrae and from the fibrocartilage between them. It ends in a long flat tendon which is insertedinto the pectineal line and iliopectineal eminence, and, by its lateral border, into the iliac fascia. This muscle is often absent.