**Core Concept**
The femoral nerve is a major nerve in the lower limb, formed by the dorsal divisions of the ventral primary rami of the lumbar plexus. The lumbar plexus is a complex network of nerves formed by the ventral primary rami of the lower thoracic and upper lumbar spinal nerves.

**Why the Correct Answer is Right**
The femoral nerve arises from the dorsal divisions of the ventral primary rami of the L2, L3, and L4 spinal nerves. This is because the dorsal divisions of these rami, which are responsible for the motor innervation of the lower limb, combine to form the femoral nerve. The ventral divisions of the same rami form the obturator nerve. The dorsal primary rami of the lumbar spinal nerves primarily supply the paraspinal muscles and skin of the back, and are not involved in the formation of the femoral nerve.

**Why Each Wrong Option is Incorrect**
**Option B:** The ventral divisions of the ventral primary rami of the lumbar nerves form the obturator nerve, not the femoral nerve.
**Option C:** The dorsal primary rami of the lumbar nerves are not involved in the formation of the femoral nerve.
**Option D:** The dorsal divisions of the dorsal primary rami of the lumbar nerves do not exist, as the dorsal primary rami do not have dorsal divisions.

**Clinical Pearl / High-Yield Fact**
The femoral nerve is often damaged in surgeries involving the lumbar plexus, such as abdominal aortic aneurysm repair or pelvic surgery. This can result in weakness or paralysis of the quadriceps muscle, leading to difficulty walking or standing.

✓ Correct Answer: A. Dorsal divisions of ventral primary rami of lumbar 2, 3, 4