Objective: To observe the structure of acupoints: "Shangyang" (LI 1), "Erjian" (LI 2), "Sanjian" (LI 3), "Hegu" (LI 4) and "Ouchi" (LI 11) of the Yangming Meridian in the rabbit's forelimb.
Methods: The acupoints were first located in accordance with the related atlas of rabbits and confirmed by low resistance and higher electric potential determinations by using a "multipurpose electronic acupoint detection and therapeutic instrument". Then the animals under anesthesia were killed by intravenous injection of air embolism, perfused with 5% natrium citricum first, acetic ether containing acrylonitrile-butadiene-styrene copolymer, and 5% dicapryl phthalate, blue and red pigments for paintings via subclavian artery, respectively. After routinely inserting an acupuncture needle into the acupoint, the local tissues (muscles, blood vessels and nerves) of the acupoints mentioned above were dissected layer by layer and their relations with the needle were observed under microscope.
Results: "Erjian" (LI 2) is situated at the depression site distal to the second metacarpophalangeal joint on the radial side. "Sanjian" (LI 3) is located at the depression site proximal to the second metacarpophalangeal joint on the radial side. The shallow-layers of "Shangyang" (LI 1), "Erjian" (LI 2), "Sanjian" (LI 3), "Hegu" (LI 4) and "Quchi" (LI 11) mainly contain cephalic vein and shallow branches of the radial nerve, and their deep layers chiefly contain radial artery and its branches, and the median nerve.
Conclusion: "Shangyang" (LI 1), "Erjian" (LI 2), "Sanjian" (LI 3), "Hegu" (LI 4) and "Quchi" (LI 11) have a close association with the cephalic vein,radial artery,radial vein and its branches,superficial branch of radial nerve and the median nerve,which constitutes the morphological basis of the five points.