Genitofemoral nerve block

Intermediate. The branches are tiny and rarely seen, so the block is done by placing the drug next to structures that are easy to see: the spermatic cord or round ligament, and the femoral artery.

The genitofemoral nerve comes from L1–L2 within psoas and runs down on the front of the muscle, then divides above the inguinal ligament.

The genital branch enters the inguinal canal at the deep ring and runs in the spermatic cord (with the round ligament in women). It supplies the cremaster muscle and the skin of the scrotum or labia majora.

The femoral branch passes under the inguinal ligament inside the femoral sheath, on the front and side of the femoral artery, and supplies the skin of the upper front thigh over the femoral triangle.

The ilioinguinal and iliohypogastric nerves supply the nearby skin, so an ilioinguinal–iliohypogastric block alone often misses the genital branch and the cord traction pain.

• Pubic tubercle and anterior superior iliac spine (inguinal ligament between them).
• Mid-inguinal point and femoral pulse.
• Deep ring: about 1–2 cm above the midpoint of the inguinal ligament.

• Open inguinal hernia repair, with an ilioinguinal–iliohypogastric block.
• Orchidopexy, hydrocele and scrotal surgery (spermatic cord block).
• Femoral branch: varicose vein surgery at the groin and procedures on the upper front thigh, with other blocks.
• Diagnosis and treatment of genitofemoral neuralgia, for example after hernia repair or caesarean section.

• Genital branch of the genitofemoral nerve (L1–L2)
• Femoral branch of the genitofemoral nerve
• A spermatic cord injection also blocks the sympathetic fibres to the testis

Surface anatomy, relevant structures and landmarks

Genital branch: just lateral to the pubic tubercle, below the inguinal ligament, where the cord is felt. Femoral branch: subcutaneous infiltration just below the inguinal ligament, lateral to the femoral pulse.

Positioning

Supine.

Block technique

• Genital branch: hold the cord at the pubic tubercle and inject 5–10 mL around it, aspirating often. The surgeon can also inject the cord directly during the operation.
• Femoral branch: fan 5 mL under the skin just below the inguinal ligament, lateral to the femoral pulse.

Needle choice

22–25 G, 25–50 mm.

Neurostimulation technique

Not used.

Choice of local anaesthetic (including volume)

• Adults: 3–5 mL per branch of 0.25–0.5% bupivacaine or levobupivacaine, or 0.2–0.5% ropivacaine.
• Children: 0.1–0.2 mL/kg for the cord, within weight-based limits.

Show scan

IPm Iliopsoas muscle

Show scan

SC Spermatic cord (genital branch of the genitofemoral nerve inside)VD Vas deferensPT Pubic tubercle

Positioning

Supine, operator on the side of the block.

Scanning technique

• Genital branch: place the probe along the inguinal ligament just above it, in line with the canal. Slide medially from the anterior superior iliac spine past the femoral vessels to find the oval spermatic cord (or round ligament) inside the canal, under the external oblique aponeurosis.
• Genital branch at the pubic tubercle: alternatively, place the probe across the cord just lateral to the pubic tubercle, where it leaves the superficial ring. The tubercle is a bright curve with a shadow underneath; the cord is the oval just above it, with the round, thick-walled vas deferens inside. Inject around and inside the cord sheath, keeping the needle tip off the vas deferens.
• Colour Doppler shows the testicular artery inside the cord and the inferior epigastric artery deep and medial to the deep ring.
• Insert the needle in plane from lateral and inject 3–5 mL around the cord, inside and outside its covering, keeping away from the vas deferens and the vessels.
• Femoral branch: place the probe across the femoral artery at the groin crease. Inject 3–5 mL just superficial and lateral to the artery, inside the femoral sheath, staying medial to the femoral nerve.

Structures to identify

• External oblique aponeurosis
• Inguinal canal and spermatic cord (or round ligament)
• Pubic tubercle
• Testicular artery and vas deferens
• Inferior epigastric artery
• Femoral artery, femoral vein and femoral nerve
• Fascia lata and fascia iliaca

Position / ergonomics

Stand on the side of the block, screen opposite.

Probe

Linear high-frequency.

Settings

Small parts preset, depth 3–4 cm, colour Doppler on.

Depth

1–3 cm for the cord; 2–4 cm for the femoral branch.

Needle size

22–25 G, 50 mm.

Needling technique

In plane from lateral to medial.

Optimal needle-tip position

Next to the spermatic cord or round ligament inside the canal; or anterolateral to the femoral artery inside the femoral sheath.

Drug choice

See above.

Volume

3–5 mL per branch in adults.

Optimal current if nerve stimulation is used

Not used.

Muscle responses acceptable

Not applicable.

Testing block success

• Numb skin of the scrotum or labia (genital branch) or upper front thigh (femoral branch)
• No pain or heart rate rise with cord traction

Not used.

• Add the genital branch to an ilioinguinal–iliohypogastric block when the cord or sac is handled.
• Use colour Doppler before injecting: the testicular and inferior epigastric arteries are close.
• For the femoral branch, stay medial and superficial so the femoral nerve is not blocked.
• For groin neuralgia, a small volume (2–3 mL) gives a cleaner diagnostic answer.

• Li and colleagues (2024) randomised 40 older adults having open inguinal hernia repair: adding the genitofemoral nerve to an iliohypogastric–ilioinguinal block reduced pain, cord traction responses and opioid use.
• Elemam and colleagues (2025) randomised 50 boys having inguinal herniotomy: adding a spermatic cord block to an ilioinguinal block reduced the need for rescue analgesia from 41% to 12%.
• Kimura and Nakajima (2026) reported relief of genital branch pain after a block of the femoral branch, suggesting spread between the two.
• Dirzu and Crivii (2026) used sequential ultrasound-guided blocks to identify and treat genitofemoral pain after caesarean section.

• Li Y, Feng X, Chen D, et al. Single-point ultrasound-guided iliohypogastric-ilioinguinal-genitofemoral nerve block for inguinal hernia surgery in older adult patients: a randomized controlled trial. Quant Imaging Med Surg 2024;14:8249–8259. PubMed
• Elemam EM, Abdelbaser I, Elbahrawy K, Alseoudy MM, El Kenany S. Efficacy of combining ultrasound-guided spermatic cord block with ilioinguinal nerve block for analgesia in pediatric inguinal herniotomy: a randomized controlled study. Rev Esp Anestesiol Reanim 2025;72:501675. PubMed
• Kimura T, Nakajima Y. Genital branch pain relief following ultrasound-guided femoral branch block of the genitofemoral nerve. Minerva Anestesiol 2026;92:248–249. PubMed
• Dirzu DS, Crivii CB. Severe postpartum inguinal neuralgia relieved by ultrasound-guided nerve blocks: a case report. Clin Case Rep 2026;14:e72047. PubMed