Which channel reaches both the inner and outer canthi of the eyes?

The small intestine channel is the correct answer because it uniquely traverses the areas around both the inner and outer canthi of the eyes in traditional Chinese medicine and acupuncture theory. According to these practices, the small intestine channel starts at the tip of the little finger and moves up through the arm, crossing the shoulder, neck, and finally reaching the face. This channel specifically connects to the areas around the eyes, indicating its role in regulating functions related to vision and perception.

In contrast, the other channels listed do not have the same anatomical trajectory that includes both canthi. The heart channel primarily focuses on the central aspects of the chest and may reach the face, but does not connect to the eyes directly at both canthi. The large intestine channel, while also reaching the face, does not extend to both the inner and outer canthi. The liver channel has a pathway that runs along the inner thigh and does connect to the eye region, but it primarily focuses on the inner canthus, making the small intestine channel the most comprehensive choice for reaching both canthi.