Which nerve is cautioned against when performing acupuncture at SP-12?

The nerve that is cautioned against when performing acupuncture at SP-12 is the femoral nerve. SP-12, also known as "Yin Bao," is located in the area of the inguinal region, which is close to the pelvis and can approach the pathway of the femoral nerve.

When needling at SP-12, practitioners should be aware of the anatomy of the region, as the femoral nerve runs beneath the inguinal ligament and can be in proximity to the acupuncture point. Accidental injury to the femoral nerve could result in complications, including motor or sensory deficits, especially since this nerve innervates muscles involved in hip flexion and contributes to sensation in the anterior thigh.

In contrast, the ulnar, radial, and median nerves are primarily located in the upper limb. Their pathways do not intersect with the area surrounding SP-12, nor do they pose a risk during procedures performed in this lower abdominal region. Thus, cautious attention to the femoral nerve during acupuncture at SP-12 is essential for patient safety and effective practice.