**Core Concept**
The lacrimal punctum, also known as the lacrimal canal or tear duct, is a small opening located at the inner corner of the eyelid. It is part of the lacrimal apparatus, responsible for draining tears from the eye into the nasal cavity.

**Why the Correct Answer is Right**
The lacrimal punctum is located at the medial (inner) canthus of both the upper and lower eyelid, allowing tears to flow from the eye into the nasolacrimal sac and eventually into the nasal cavity. The correct location of the lacrimal punctum is essential for proper tear drainage and eye health.

**Why Each Wrong Option is Incorrect**
**Option A:** The lacrimal punctum is not located at the lateral (outer) canthus of the upper or lower eyelid, which is the area where the eyelashes are found.
**Option B:** The lacrimal punctum is not located at the center of the eyelid, but rather at the medial canthus where the upper and lower eyelid meet.
**Option C:** The lacrimal punctum is not located at the lateral corner of the eye, but rather at the medial corner where the upper and lower eyelid meet.

**Clinical Pearl / High-Yield Fact**
It's essential to know the correct location of the lacrimal punctum to diagnose and treat conditions such as nasolacrimal duct obstruction or epiphora (excessive tearing).

**Correct Answer:** C.