The Hu-Chang theory is widely used in Chinese external medicine diagnosis and treatment, and it has been documented in many archives and recordings. However, its provenance and connotation were still confusing and unclear. It was believed that The Covert Prescription for External Medicine (Mi Chuan Wai Ke Fang) by Zhao Yizhen in the late Yuan and early Ming Dynasty was the earliest work with the use of provenance from the existing records of Hu-Chang. In terms of its connotation, it was believed by many scholars that the part of speech of Hu-Chang was an adjective-noun phrase, which means "defensive barrier", ie, "local swelling area in surgical disease". However, based on the textual research and analysis of relevant ancient documents, Hu-Chang should be a verb-object phrase, which means "the vital Qi prevents the diseased area from being infected or deteriorated". In this sense, the characteristic of Hu-Chang, the local swelling range of surgical diseases, can be named as "supervising and monitoring the field barrier".
护场理论在中医外科诊疗中被广泛使用，记载护场的文献也很多，但对护场出处和内涵的认识还存在一些混乱现象，有待进一步明确。目前，关于护场的出处有三种说法。经考，元末明初赵宜真《秘传外科方》应是现存最早记载护场的著作。许多中医学者认为“护场”一词属于偏正短语，将其理解为防御性屏障，即“外科疾病中的局部作肿范围”，但其实这并不是护场的最初内涵。通过对古代相关文献进行考证分析后认为，“护场”当为动宾短语，意为正气监视围困发病区域。为避免歧义，护场的主要表现（四周红肿），可被命名为“护场屏障”。.