**Core Concept**
Prostatic metastasis refers to the spread of prostate cancer to distant sites in the body. This process involves the hematogenous route, where cancer cells break away from the primary tumor, enter the bloodstream, and lodge in new locations. The most common site for prostatic metastasis is the axial skeleton, particularly the vertebral bodies.

**Why the Correct Answer is Right**
The vertebral bodies are a common site for prostatic metastasis due to their rich blood supply and the presence of red marrow, which provides a fertile ground for cancer cell seeding. The metastatic cells typically involve the vertebral bodies through the Batson vertebral vein plexus, a valveless venous system that allows cancer cells to bypass the lungs and directly reach the vertebral bodies. This phenomenon is known as the "Batson pathway."

**Why Each Wrong Option is Incorrect**
**Option A:** Lymph nodes are a common site for metastasis in many cancers, but they are not the most common site for prostatic metastasis.
**Option B:** The liver is a common site for metastasis in gastrointestinal cancers, but it is not the most common site for prostatic metastasis.
**Option C:** The lungs are a common site for metastasis in many cancers, but they are not the most common site for prostatic metastasis.

**Clinical Pearl / High-Yield Fact**
The Batson vertebral vein plexus is a critical pathway for prostatic metastasis, and its involvement is often associated with vertebral body metastases. This knowledge is essential for radiologists and clinicians to recognize and manage prostatic cancer metastasis to the spine.

**Correct Answer:** C. Vertebral bodies.