Which point is located directly below the outer canthus?

The point located directly below the outer canthus is SI-18, also known as "Collarbone's Bone." This point is situated at the lower border of the zygomatic bone, directly beneath the outer canthus of the eye. Its precise location allows it to play a role in addressing conditions related to the face and especially the region around the eyes, such as facial paralysis, pain, and swelling.

In Traditional Chinese Medicine, acupoints like SI-18 are also thought to affect the flow of Qi (or life energy) in the corresponding meridians, which is crucial for maintaining balance and health in those areas. The importance of understanding the anatomical landmarks in relation to acupuncture points is key for effective treatment strategies.

The other options, while they are also associated with the Small Intestine meridian, are not located directly beneath the outer canthus. SI-17 is found near the angle of the jaw, SI-19 is located slightly more anteriorly and superiorly relative to the ear, and SI-7 is positioned on the forearm, significantly away from the facial region. Thus, SI-18 is the only correct choice for this particular anatomical position.