Genitofemoral Nerve

Original Editor - Mohit Chand

Top Contributors - Mohit Chand, Kim Jackson and Aminat Abolade  

Introduction

The genitofemoral nerve originates from the lumbar plexus, emerging within the psoas major muscle by combining the anterior rami of the L1 and L2 spinal nerves at the lumbar spine. Descending through the retroperitoneum, it divides into genital and femoral terminal branches. These branches provide sensory innervation to the skin covering the anterior scrotum or labia majora and the lateral femoral triangle, respectively.

Anatomy

Origin

The genitofemoral nerve (GFN) arises from the lumbar plexus, emerging within the psoas major muscle by combining the anterior rami of spinal roots L1 and L2 of Lumbar spine.

Course

The GFN passes downwards within the substance of the psoas major muscle, eventually emerging on the muscle's anterior surface, and possibly the psoas minor muscle when present, deep to the psoas fascia.

In the retroperitoneum, the GFN lies posterior to the ureter, gonadal vessels, and abdominal vessels. On the left, the nerve passes deep to the left ureter and gonadal vessels, left colic artery, and the inferior mesenteric vein. On the right, the nerve passes deep to the right ureter and gonadal vessels, and the ileocolic artery and vein. Just above the inguinal ligament, both left and right genitofemoral nerves perforate the psoas fascia and divide into genital and femoral branches.

Function

• The femoral branch supplies sensory cutaneous innervation to the skin of the upper anterior thigh.
• The genital branch innervates the cremaster muscle of the spermatic cord in males and the mons pubis, labia majora, and adjacent thigh in females.

The cremasteric reflex is a function of genitofemoral nerve innervation.

Clinical Significance

The genitofemoral nerve is susceptible to injury in various situations, including:

• Groin Injury: Laceration can occur during penetrating trauma, knife wounds, or surgical exploration of the groin. Surgical procedures on the saphenous vein, such as varicose vein ligation, may cause abrasive injury with retractors.
• Inguinal Hernia Repair: Injuries can occur during inguinal hernia repair in the inguinal canal. In many cases, the injury is not immediately apparent during surgery but becomes evident postoperatively when the patient experiences pain.
• Motor Vehicle Accidents: Injuries to the genitofemoral nerve can happen during a motor vehicle accident, particularly when there is lower back injury with extension while seated.
• Heavy Lifting: Lifting heavy objects is another potential cause of genitofemoral nerve injury.
• Spinal Issues: Conditions such as spinal stenosis of the L1 or L2 segments, compression fractures, or metastatic lesions in the lumbar spine can lead to injury of the nerve roots giving rise to the genitofemoral nerve.
• Psoas Abscess: Conditions like a psoas abscess, which may occur after an open pelvic fracture or a retroperitoneal hematoma, can cause irritation of the genitofemoral nerve.

Anatomical Variation

Almost 50% of genitofemoral nerves examined in cadaveric studies demonstrated an anatomical variation.

In about 20% of cases, nerves bifurcated prematurely, occurring at the upper portion of the anterior surface of the psoas major muscle instead of the mid-portion. Occasionally, the genital and femoral branches did not converge into a common trunk within the psoas muscle but remained distinct nerves as they entered the pelvis.