A multilevel variation of the sensory branches of the lumbar plexus with an accessory genitofemoral nerve

The lumbar plexus is one of the most variable nerve plexuses in the human body. Located posteriorly to the psoas major muscle, it is the origin of several nerves that cross the retroperitoneal space and are responsible for the innervation of the lower abdominal wall and a portion of the lower limb. Relative to their anatomical route, these nerves can be divided into several major sections: intrapsoas, retroperitoneal, and distal to the inguinal ligament, and all of those are liable to nerve injury during surgical interventions. Here, we describe a complex variation involving the lateral femoral cutaneous nerve, the femoral branch of the genitofemoral nerve, and the anterior femoral nerve, discovered during a routine dissection in an undergraduate human anatomy course for medical students.