**Core Concept**
Circumorbital ecchymosis, also known as periorbital ecchymosis or "raccoon eyes," is a condition characterized by the presence of hemorrhagic discoloration around the eyes. This condition is typically associated with a fracture of the base of the skull, specifically the anterior cranial fossa.

**Why the Correct Answer is Right**
Circumorbital ecchymosis occurs due to the extravasation of blood from the bridging veins that connect the eyes to the superior sagittal sinus. This happens when there is an increase in intracranial pressure, such as in the case of a basal skull fracture. The blood tracks down through these veins and appears as a bruise around the eyes.

**Why Each Wrong Option is Incorrect**
* **Option A:** Fracture of the anterior wall of the maxillary sinus might cause ecchymosis around the cheek and nose, but it is not typically associated with circumorbital ecchymosis.
* **Option B:** Fracture of the zygomatic bone can cause ecchymosis around the eye, but it is not typically associated with circumorbital ecchymosis.
* **Option C:** Fracture of the base of the skull, specifically the anterior cranial fossa, is a classic cause of circumorbital ecchymosis.

**Clinical Pearl / High-Yield Fact**
Circumorbital ecchymosis is a "saddleback" sign, where the ecchymosis is present both above and below the eyebrows, indicating a fracture of the anterior cranial fossa.

**Correct Answer:** C. Fracture of the base of the skull, specifically the anterior cranial fossa, is a classic cause of circumorbital ecchymosis.