Genitofemoral nerve : lecture note including clinical significance

Genitofemoral nerve

1.    Plexus

2.    Root value & type

3.    Relation

4.    Branches

5.    Distribution

6.    Function

7.    Nerve block

8.    Clinical importance

1.    Plexus :  It is arises from lumbar plexus

2.    Root value : ventral divisions fo L1 and 2

3.    Type : mixed nerve ( both motor and sensory )

4.    Branches :  The nerve divides into two branches, the genital branch and the lumboinguinal nerve also known as the femoral branch,

5.    Relation : It passes downwards, pierces the psoas major and emerges from its anterior surface. Genital and femoral branch of genitofemoral nerve then continue downwards and medially to the inguinal and femoral canal respectively.

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6.    Distribution :

Distribution of Genital branch of genitofemoral nerve:

The genital branch passes through the deep inguinal ring and enters the inguinal canal.

In male, the genital branch supplies the cremaster and scrotal skin.

In female , the genital branch accompanies the round ligament of uterus, terminating in and innervating the skin of the mons pubis and labia majora

Distribution of femoral branch of genitofemoral nerve :

The femoral branch passes underneath the inguinal ligament, travelling through the lateral muscular compartment of the femoral canal where it innervates skin of the upper leg. Passing through the cribriform fascia of the saphenous opening of the fascia lata of the thigh, it then supplies the skin of the upper, anterior and medial side of thigh

7.    Variation : In this study of 200 bodies (400 nerves), 80.2% presented as a single trunk and 19.75% as two rami: genital and femoral. The trunk or rami were usually formed by nerve fibers from L1, L2 from the lumbar plexus. The level of emergence of the nerve or nerves from the psoas major muscle and the level of division into terminal branches were individually highly variable. These characteristics were unrelated to each other, sex, age, height or weight or side of the body. The genitofemoral nerve was present in all cases. Two types were recognized. In type I, the trunk of the nerve divided into two main rami: genital and femoral. In type II, the rami arose separately from the lumbar plexus. Type I was present bilaterally in 70.5%, and type II in 10% of cases.

Spinal nerve L1, was present in nearly all cases, and L2 in all cases sent fibers to the genitofemoral nerve. Fibers from L3 were present in only 0.75% of cases.

8.    Function : femoral branch give sensory supply at the anteromedial aspect of thigh over the femoral triangle

9.    Genital branches gibe sensory supply tunica vaginalis, spermatic fasciae, small area of anterior scrotal skin and in female round ligament of uterus , skin of mons pubis and labium majus

10. Nerve block :  genitofemoral nerve lies immediately lateral to the spermatic cord as it emerges from the superficial Inguinal ring . The spermatic cord Is identified immediately lateral to the pubic tubercle.

 The area for injection, including the scrotum, Is sterilised.

 The spermatic cord is then stabilised and medlallsed using the nondominant hand, and 5ml of 1% lldocaine Is injected subdermally, Immediately lateral to the cord, superficial to the bone.

 Negative aspiration prior to injection ensures non-penetrance of the peritoneum or femoral vessels.

Clinical Significance

The genitofemoral nerve can be injured during surgery in several ways:

• It can be lacerated during injury to the groin. This can occur with penetrating trauma, a knife wound or surgical exploration of the groin. In some cases, during surgery on the saphenous vein for varicose vein ligation, retractors can cause abrasive injury.
• The genitofemoral nerve can also be injured in the inguinal canal, usually during inguinal hernia repair. In most cases, the injury is unnoticed during surgery and diagnosed in the post operative period when the patient complains of pain.
• Lifting heavy objects can also cause injury to the genitofemoral nerve.
• When there is spinal stenosis of the L1 or L2 segments, compression fracture or metastatic lesions to the lumbar spine the nerve roots which give rise to the genitofemoral nerve can be injured.
• Psoas abscess which may occur after an open pelvic fracture or a retroperitoneal hematoma is also known to cause irritation of the genitofemoral nerve.
• Genitofemoral neuralgia is a relatively common pain syndrome observed in both males and females. The patient typically presents with unilateral pain in the lower abdomen. Rarely the pain may be bilateral. The pain is sometimes referred to the groin area (because of the path of the genital nerve) and the upper medial thigh (because of the femoral branch). The pain varies in intensity from moderate to severe and is worsened by movements that cause extension of the lower back. In most patients, palpation of the lower abdomen in the inguinal region can reproduce the pain. In most cases, the cause is compression of the nerve in the inguinal canal, usually after open hernia surgery. The diagnosis is often difficult in patients who have not had surgery.