The lumboinguinal nerve (femoral or crural branch of genitofemoral) descends on the external iliac artery

External iliac artery

The external iliac arteries are two major arteries which bifurcate off the common iliac arteries anterior to the sacroiliac joint of the pelvis. They proceed anterior and inferior along the medial border of the psoas major muscles...

, sending a few filaments around it, and, passing beneath the inguinal ligament

Inguinal ligament

The inguinal ligament is a band running from the pubic tubercle to the anterior superior iliac spine. Its anatomy is very important for operating on hernia patients.-Anatomy:...

, enters the sheath of the femoral vessels, lying superficial and lateral to the femoral artery

Femoral artery

The femoral artery is a general term comprising a few large arteries in the thigh. They begin at the inguinal ligament and end just above the knee at adductor canal or Hunter's canal traversing the extent of the femur bone....

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It pierces the anterior layer of the sheath of the vessels and the fascia lata

Fascia lata

-Thickness:It is an investment for the whole of the thigh, but varies in thickness in different parts.Thus, it is thicker in the upper and lateral part of the thigh, where it receives a fibrous expansion from the Glutæus maximus, and where the Tensor fasciæ latæ is inserted between its layers; it...

, and supplies the skin of the anterior surface of the upper part of the thigh

Thigh

In humans the thigh is the area between the pelvis and the knee. Anatomically, it is part of the lower limb.The single bone in the thigh is called the femur...

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On the front of the thigh it communicates with the anterior cutaneous branches of the femoral nerve

Femoral nerve

The femoral nerve, the largest branch of the lumbar plexus, arises from the dorsal divisions of the ventral rami of the second, third, and fourth lumbar nerves...

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A few filaments from the lumboinguinal nerve may be traced to the femoral artery.