What anatomical term describes the corners of the lips?

The term that describes the corners of the lips is "commissures." These anatomical structures refer to the points where the upper and lower lips meet at either side of the mouth. The commissures play a significant role in oral function, including speech and eating, and hold importance in facial aesthetics as well.

The other terms listed refer to different anatomical features:

• "Labial angles" also relates to the corners of the lips but is less commonly used and is not the standard term compared to commissures.
• "Cheilion" specifically refers to the corner of the mouth or the junction of the upper and lower lips, but "commissures" is more widely recognized in clinical contexts.
• "Frenulum," on the other hand, refers to the small fold of tissue that secures or restricts the movement of the lips or tongue, and does not describe the corners of the lips.

Thus, "commissures" is the most accurate and widely accepted term for the anatomical features being asked about, emphasizing the specific location and role they have within the oral cavity.