Saphenous Nerve: Anatomy, Course, Relations, Function, Clinical Significance, MRI & CT Imaging

Topic

Saphenous nerve

The saphenous nerve is the largest cutaneous branch of the femoral nerve, responsible for sensory innervation of the medial aspect of the leg and foot. It descends through the thigh within the adductor canal and accompanies the great saphenous vein in the leg. It is clinically important in peripheral neuropathies, entrapment syndromes, and surgical interventions involving the knee or medial leg.

Synonyms

Medial cutaneous branch of femoral nerve
Long saphenous nerve
Sensory branch of femoral nerve

Origin, Course, and Termination

Origin: Arises from the femoral nerve in the femoral triangle (roots L3–L4)
Course:
- Descends within the adductor canal, anterior to the femoral artery
- Emerges at the medial knee by piercing the sartorius and vastoadductor membrane
- Travels with the great saphenous vein along the medial leg
Termination:
- Ends as cutaneous branches supplying the medial side of the leg, ankle, and foot up to the great toe

Relations

Proximally: Femoral artery and vein within the femoral triangle
Within adductor canal: Lies anterior to femoral artery, deep to sartorius
At the knee: Pierces sartorius muscle and fascial plane
In the leg: Runs alongside the great saphenous vein, superficial to fascia, and medial to tibia

Function

Purely sensory nerve
Provides cutaneous innervation to:
- Medial thigh (partially)
- Medial leg
- Medial malleolus and foot up to the hallux

Clinical Significance

Entrapment neuropathy in the adductor canal can cause medial leg pain and paresthesia
Vulnerable during saphenous vein harvesting, varicose vein surgery, and knee surgery
Injury results in sensory loss along medial leg and foot
Saphenous nerve block used in regional anesthesia for knee and ankle procedures
Target for ultrasound-guided injections in pain management