**Core Concept**
The thyroid gland is surrounded by a network of veins that drain its blood supply. The fourth thyroid vein, also known as Kocher's vein, is an accessory vein that may be present in some individuals. Understanding the anatomy of thyroid veins is essential for surgeons and anesthesiologists to plan and perform procedures safely.

**Why the Correct Answer is Right**
The fourth thyroid vein is typically found between the **inferior thyroid vein** and the **external jugular vein**. This anatomical location is significant because it can be a potential site for bleeding during thyroid surgery. The presence of Kocher's vein can also affect the surgical approach and the choice of venous access sites.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not a recognized location for the fourth thyroid vein.
* **Option B:** The second thyroid vein is not typically associated with Kocher's vein.
* **Option C:** The superior thyroid vein is not a correct location for the fourth thyroid vein.

**Clinical Pearl / High-Yield Fact**
Kocher's vein may be an incidental finding during thyroid surgery, and its presence should be noted to avoid potential complications.

**Correct Answer:** C.