Quick Facts
Origin: From the anterior rami of first and second lumbar nerves (L1—L2).
Course: Descends on the anterior surface of psoas major muscle, behind the parietal peritoneum, ureter, and abdominal vessels.
Branches: Genital and femoral branches.
Supply: The genital branch supplies motor innervation to cremaster muscle, and sensory cutaneous innervation for the upper anterior part of scrotum (males), or mons pubis, and labium majus (females). The femoral branch supplies sensory cutaneous innervation to the skin of the upper anterior thigh (femoral branch).
Related parts of the anatomy
Origin
The genitofemoral nerve is formed within the substance of the psoas major muscle by the union of branches from the anterior rami of the first and second lumbar nerves (L1-L2).
Course
Following its origin from the anterior rami of the first and second lumbar nerves, the genitofemoral nerve continues to descend inside the substance of the psoas major muscle. It pierces the muscle to emerge on its anterior surface (Reinpold et al., 2015). It then descends further in the retroperitoneum, on the anterior surface of the muscle, while passing deep to the ureter, gonadal vessels, left colic artery, and inferior mesenteric vein (replaced by ileocolic artery and vein on the right side).
The nerve eventually pierces the psoas fascia and divides into genital and femoral branches just superior to the inguinal ligament.
Branches
The genital branch descends and passes through the deep inguinal ring to enter the inguinal canal. It becomes superficial and terminates on the skin in the upper anterior part of the scrotum (males), or it accompanies the round ligament of the uterus and terminates on the skin of the mons pubis and labium majus (females).
The femoral branch descends on the lateral side of the external iliac artery and passes underneath the inguinal ligament. It enters the femoral sheath lateral to the femoral artery. It then pierces the anterior layer of the femoral sheath and the fascia latae to terminate on the skin of the upper anterior thigh (femoral triangle).
Supplied Structures
The genital branch is a mixed nerve containing both somatic efferent (motor) and afferent (sensory) neurons.
The genital branch provides motor innervation to the cremaster muscle inside the inguinal canal. It also transmits general sensory information from the skin in the upper anterior part of the scrotum, spermatic fascia, and tunica vaginalis of testis (males), or the skin of the mons pubis, and labium majus (females).
The femoral branch is purely sensory nerve containing information from the skin of the upper anterior thigh.
References
Reinpold, W., Schroeder, A. D., Schroeder, M., Berger, C., Rohr, M. and Wehrenberg, U. (2015) 'Retroperitoneal anatomy of the iliohypogastric, ilioinguinal, genitofemoral, and lateral femoral cutaneous nerve: consequences for prevention and treatment of chronic inguinodynia', Hernia, 19(4), pp. 539-48.
