Related Experiment Video
Updated: May 5, 2026

Cervical Lymph Duct-Cannulated Rat Model for Assessing Lymphatic Transport from the Head and Brain
Published on: March 10, 2026
Primo vascular system floating in lymph ducts of rats
Sharon Jiyoon Jung1, Kyoung-Hee Bae, Min-Ho Nam
1Nano Primo Research Center, Advanced Institute of Convergence Technology, Seoul National University, Suwon, South Korea; Graduate School of Convergence Science and Technology, Seoul National University, Suwon, South Korea.
Abstract:
An epoch-making development in the gross anatomy of the lymph system has emerged: the observation of the primo vascular system (PVS), which is a threadlike structure floating in lymph ducts. The PVS, which was proposed as the conduit for the acupuncture Qi, is a complex network distributed throughout an animal's body. The lymph-PVS, which is a subsystem of the PVS, is one of the most convincing visual demonstrations of the PVS. Because its existence is not easily demonstrated, even with a microscope, due to its transparency, in current anatomy its existence is largely unknown despite its potential significance in physiology and medicine. The lymph-PVS has been observed in rabbits, rats, and mice by several independent teams. Because the involved techniques are rather complicated, we provide detailed protocols for surgery, for injection of the staining dye, and for detection, extraction, and identification of the PVS in a rat.
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