**Question:** Lymphatic drainage of cervix is to

A. Right common iliac lymph node
B. Left common iliac lymph node
C. External iliac lymph node
D. Supracervical lymph node

**Core Concept:**

Lymphatic system plays a crucial role in the defense mechanism of the human body by collecting lymph, a clear fluid containing waste products, pathogens, and cells, and transporting it to the lymph nodes for filtration and processing. In the context of cervical lymphatic drainage, the cervix is part of the female reproductive system and is drained by the uterine lymphatics.

**Why the Correct Answer is Right:**

The correct answer is **C. External iliac lymph node**, as it is the most appropriate site for the cervical lymphatic drainage. The cervix lies in the pelvis, and the external iliac lymph nodes are part of the pelvic lymphatic drainage system. They are located on the outer side of the iliac vessels, which are part of the abdominal aorta and inferior vena cava. The lymphatic vessels from the cervix merge with the external iliac lymph nodes, which then carry the filtrate to the common iliac lymph nodes and finally to the para-aortic lymph nodes.

**Why Each Wrong Option is Incorrect:**

- **A. Right common iliac lymph node**: The cervix is drained by the external iliac lymph nodes, not the common iliac lymph nodes. The common iliac lymph nodes receive filtrate from the external iliac lymph nodes, but they are not the primary site for cervical drainage.

- **B. Left common iliac lymph node**: Similar to option A, the left common iliac lymph nodes are not the primary site for cervical drainage. The cervix is drained by the external iliac lymph nodes, which then drain into the left common iliac lymph nodes.

- **D. Supra-cervical lymph node**: The cervix has its own lymphatic drainage system and does not directly communicate with supracervical lymph nodes. The cervical lymphatic drainage follows the external iliac lymphatic vessels and ends in the external iliac lymph nodes, which further drain into the common iliac lymph nodes and finally into the para-aortic lymph nodes.

**Clinical Pearl:**

Understanding the correct lymphatic drainage of the cervix is crucial for clinical practice, as it aids in diagnosing and treating gynecological conditions, such as cervical cancer, which might affect lymph nodes in these regions. Knowledge of these drainage pathways is essential for proper management of patients with cervical disorders.