本文透過文獻檢閱方式，討論國際健康、功能與身心障礙分類系統（International Classification of Functioning, Disability and Health, 以下簡稱ICF）架構內重要功能概念，當年提出時的主要論點。本文以第一位提出【功能限制】的美國社會學家Sasd Z. Nagi的相關論文為主要的分析焦點。目前台灣正在嘗試推動採取ICF架構做為評估障礙狀態的參考架構。對大多數台灣臨床工作者而言，涉及臨床判定時，數值碼的選定以及如何做判斷是最重要的關鍵。在ICF架構中，「功能限制」是極具關鍵性的概念，也是整個模型的重點。本文由幾篇Nagi的重要文獻開始，檢閱最初始的討論與後期別人如何呈現他的論點，以確證抽象概念層次的意義與如何在後期轉化為具體的臨床運用碼之間的關係。

This study takes retrospective analysis on Nagi work on functional limitation. By in depth analysis couple of his papers published in different years, Nagi and his contribution to ICF system is clearly presented in this paper. Currently, ICF system has been introduced to Taiwan, under which various clinicians need to make decisions on coding process. It is important to know how and why certain code has to be made in certain way. The author takes a retrospective approach to examine the original meaning behind current coding system. It is clear that Nagi his influence to current ICF frameworks and coding system. Even after four decades, his view on the relationship between functional limitation, disability and impairment is still stand for. The final part of this paper further describes the functional limitation and its relation to universalism principle and how those two principles might eventually lead to society changes attitudes toward people with disabilities.