## **Core Concept**
Carcinoma of the lower lip is a type of skin cancer that can metastasize to regional lymph nodes. The lymphatic drainage of the lower lip is primarily to the lymph nodes in the neck.

## **Why the Correct Answer is Right**
The correct answer, **D. Submandibular lymph nodes**, is right because the lower lip drains lymphatically to the submandibular lymph nodes. These nodes are located under the mandible (jawbone) and are a common site for metastasis from cancers of the lower lip. The lymphatic drainage pathway for the lower lip involves the labial lymphatic vessels that drain into the submandibular lymph nodes.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because while some cancers can metastasize to distant sites, the question specifically asks about secondaries (metastases) in the context of carcinoma of the lower lip, implying regional lymph nodes rather than distant sites.
- **Option B:** This option is incorrect because, although lymph nodes are involved, the specificity to "cervical" is too broad and does not accurately reflect the primary site of drainage for the lower lip.
- **Option C:** This option is incorrect because the parotid lymph nodes are not the primary site for lymphatic drainage of the lower lip.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the lymphatic drainage of the lip is typically to the **submandibular lymph nodes** for the lower lip and to the **preauricular and parotid lymph nodes** for the upper lip. This knowledge helps in assessing the risk of lymph node metastasis in lip cancer.

## **Correct Answer: D. Submandibular lymph nodes**