Answer:
The origin of the quadratus lumbar muscle is the lower edges of the transverse processes of the lumbar vertebrae (L1-L5), internal surface of the ilium, sides of the bodies of the last thoracic vertebra (T12), all lumbar vertebrae (L1- L5 ), intervertebral fibrocartilages and base of the sacrum.
Step-by-step explanation:
We are referring to the quadratus lumbar muscle, therefore to the iliotransverse muscle fibers.