Final answer:
The posterior wall of the inguinal canal is formed by the lumbar vertebrae, parts of the ilia of the hip bones, psoas major and iliacus muscles, and quadratus lumborum muscle.
Step-by-step explanation:
The posterior wall of the inguinal canal is formed by the lumbar vertebrae, parts of the ilia of the hip bones, psoas major and iliacus muscles, and quadratus lumborum muscle. These structures make up the posterior abdominal wall, which has an important role in stabilizing the body and maintaining posture.