A patient underwent surgery for the varicose vein. He now complains of sensory loss over the medial aspect of the leg and foot. Which of the following nerves is most likely to be injured?

Explanation

## Correct Answer: D. Saphenous nerve The saphenous nerve is the sensory continuation of the femoral nerve and is the **longest sensory nerve in the body**. It descends along the medial aspect of the leg, passing through the adductor canal (Hunter's canal) before emerging to supply sensation to the medial leg, medial knee, and medial foot including the medial border of the foot and great toe. During varicose vein surgery, the **greater saphenous vein (GSV)** is the primary target for stripping or ligation, and this vein runs intimately alongside the saphenous nerve throughout its course down the medial leg. The nerve is at high risk of injury during GSV stripping, particularly in the lower third of the leg where the vein and nerve are in close anatomical proximity. Sensory loss over the medial aspect of the leg and foot is the classic presentation of saphenous nerve injury—this is a well-recognized complication of varicose vein surgery in Indian surgical practice. The patient's complaint of medial leg and foot sensory loss directly correlates with the saphenous nerve's sensory distribution, making it the most likely injured nerve. ## Why the other options are wrong **A. Sural nerve** — The sural nerve is a sensory nerve that supplies the **lateral aspect of the leg and lateral border of the foot**. It is formed by branches of the tibial and common peroneal nerves in the popliteal fossa. While it can be injured during lower limb surgery, it would cause sensory loss over the lateral leg and foot, not the medial aspect. The sural nerve is not closely associated with the greater saphenous vein's course. **B. Deep peroneal nerve** — The deep peroneal nerve supplies the **anterior compartment of the leg** and provides sensory innervation to the first web space between the great toe and second toe. It is not involved in the medial leg sensory supply. Deep peroneal nerve injury would present with foot drop and sensory loss over the dorsum of the foot, not the medial aspect. This nerve is not at risk during standard varicose vein surgery. **C. Superficial peroneal nerve** — The superficial peroneal nerve supplies the **lateral compartment of the leg** and provides sensory innervation to the lateral leg and dorsum of the foot. Injury would cause sensory loss over the lateral leg and foot, not the medial aspect. The superficial peroneal nerve has no anatomical relationship with the greater saphenous vein and is not at risk during varicose vein surgery. ## High-Yield Facts - **Saphenous nerve** is the longest sensory nerve in the body and the terminal sensory branch of the femoral nerve. - **Greater saphenous vein (GSV)** runs alongside the saphenous nerve throughout the medial leg, making the nerve vulnerable during GSV stripping. - **Saphenous nerve injury** is the most common neurological complication of varicose vein surgery, causing medial leg and foot sensory loss. - The saphenous nerve passes through the **adductor canal (Hunter's canal)** before emerging to supply the medial leg and foot. - **Medial leg and medial foot sensory loss** is the classic presentation of saphenous nerve injury post-varicose vein surgery. ## Mnemonics **Saphenous = Medial (SAM)** **S**aphenous = **M**edial leg/foot. Remember: Saphenous Always supplies the Medial aspect. Use this when asked about medial leg sensory loss after varicose vein surgery. **GSV Stripping Complication** **G**reater **S**aphenous **V**ein stripping → **S**aphenous nerve injury → **S**ensory loss (medial leg). The vein and nerve are inseparable anatomically. ## NBE Trap NBE may pair **sural nerve** with varicose vein surgery to trap students who confuse lateral vs. medial leg sensory distributions. The sural nerve is also a sensory nerve of the lower leg, but it supplies the lateral aspect—not the medial aspect described in the question. ## Clinical Pearl In Indian surgical practice, saphenous nerve injury is reported in 10–30% of GSV stripping procedures. Patients often present with a patch of numbness over the medial ankle and foot—a minor but persistent morbidity that should be counseled preoperatively. Modern endovenous techniques (EVLT, RFA) used in urban Indian centers reduce this complication significantly. _Reference: Bailey & Love Ch. 65 (Varicose Veins); Robbins Ch. 27 (Peripheral Nerve Injuries)_