Lateral Femoral Cutaneous Nerve
The lateral femoral cutaneous nerve of the thigh (LFCN) is a pure sensory nerve that supplies the anterolateral thigh. The topics of Meralgia Paraesthetica and lateral femoral cutaneous nerve injections are dealt with elsewhere.
Origin and Route
The LFCN arises from the lumbar plexus, originating from L2 and L3. It starts from between the superficial and deep parts of the psoas muscle and goes around the pelvis on the iliacus muscle between two layers of fascia. It then travels through an “aponeuroticofascial tunnel” that courses from the iliopubic tract to the inguinal ligament, under the inguinal ligament or through an opening in the lateral aspect at the ASIS. Around 10cm below the inguinal ligament, it exits through the superficial fascia of the thigh, and divides into anterior and posterior branches. It terminates in the skin of the anterolateral thigh.
Sensory Distribution
The LFCN has two branches, the anterior (larger) branch, and the posterior (smaller) branch. The anterior branch supplies the anterolateral thigh to the knee. The posterior branch supplies the greater trochanter to the area supplied by the anterior division.
Motor Distribution
There are no motor fibres.
Anatomic Variability
Other Relevant Structures
- Transversus abdominis muscle
- This may partially originally from the iliacus fascia, and so abdominal contraction can increase stress on the LFCN.
- Iliopubic tract
- The LFCN can be compressed here, which is analogous to median nerve entrapment in carpal tunnel syndrome.
- Inguinal ligament
- Many structures converse on the inferior border of the oblique aponeurosis. This includes the fascia lata and also the origin of sartorius.
- Muscular compartment of the inguinal region
- Between the inguinal ligament, the iliopectineal arch, and the ilium, through which the LFCN, femoral nerve, and iliopsoas muscle reach the leg
- Deep circumflex vessels
- The LFCN passes deep to these vessels as it approaches the ASIS.
References
- Trescot, Andrea. Peripheral nerve entrapments : clinical diagnosis and management. Switzerland: Springer, 2016.
