**Core Concept**
The lymphatic drainage of the lower limb is a complex system involving multiple nodes and pathways. The deep inguinal lymph nodes are a crucial part of this system, acting as a filter for lymph from the lower limb. These nodes are located in the femoral canal, near the femoral artery and vein.

**Why the Correct Answer is Right**
The correct answer is related to the lymphatic drainage of the lower limb. The superficial inguinal lymph nodes receive lymph from the skin of the lower limb, whereas the deep inguinal lymph nodes receive lymph from the muscles and deep structures of the lower limb. The deep inguinal lymph nodes are a critical component of the lymphatic system, as they filter lymph that has not passed through the superficial nodes. This lymph is then drained into the iliac lymph nodes, which eventually drain into the thoracic duct.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the superficial inguinal lymph nodes receive lymph from the skin of the lower limb, not the deep structures.

**Option B:** This option is incorrect because the popliteal lymph nodes receive lymph from the posterior aspect of the knee, not the deep inguinal lymph nodes.

**Option C:** This option is incorrect because the external iliac lymph nodes receive lymph from the abdominal wall, not the deep inguinal lymph nodes.

**Clinical Pearl / High-Yield Fact**
It is essential to remember the lymphatic drainage pathways of the lower limb, as knowledge of these pathways is crucial for understanding the spread of cancer and other diseases in this region.

**Correct Answer:** C. Gluteal and perineal lymphatics.