The lumbar plexus is shaped lateral for the intervertebral foramina from the ventral rami of the very first 4 lumbar spinal nerves (L1-L4), which all pass through psoas major. The greater branches with the plexus exit the muscle to go sharply downward to reach the abdominal wall and the thigh https://www.sgvascularctr.com/swelling-leg-treatment-singapore/