英：quaternary; 法：quaternaire
一个四元组即由四个元素所组成的一个结构。拉康倾向于强调象征界的三角结构而拒绝各种二元图式，尽管这涉及了三元图式在其著作中占有的支配性地位（见：二元关系[DUAL REALTION]), 但是拉康也同样注重四元图式的重要性：“因为无意识的引入，所以在主体秩序化的建构中便始终需要有一种四分结构。”(Ec, 774)
在1950年代初期，有关四元组的强调首次出现在拉康的著作当中，这或许是由于克劳德·列维-斯特劳斯的影响，因为列维-斯特劳斯有关舅权制结构的著作表明了亲属关系的基本单元总是至少涉及四个项 (Lvi-Strauss, 1945)。因而，在1953年的一篇处理神经症患者“个人神话”(individual myth)的文章里 (这也是对于列维-斯特劳斯的另一处参照)，拉康便评论说“在神经症患者的内部存在着一种四重奏的情境”(Lacan, 1953b:231), 他还补充说相比于俄狄浦斯情结在传统上的三角主题化，这种四重奏能够更加严格地示范每例神经症个案的特殊性 (Lacan, 1953b:235)。他就此得出结论：“整个俄狄浦斯图式都需要重新审视。”(Lacan, 1953b:235)因而，除了俄狄浦斯情结的三个元素 (母亲、孩子、父亲)之外，拉康还常常会讲到第四个元素，他有时声称这第四个元素是死亡 (DEATH)(Lacan, 1953b:237: S4,431),而有时又指出它是阳具 (PHALLUS)(S3,319).
在1955年，拉康继而把精神分析治疗比作桥牌，即“一种适合四个玩家的游戏”(E, 139: 见：E, 229-30)。同年，他又把四元组描述为由一个三元结构加上在此三元素中间循环的第四元素 (即字符[LETTER])而构成的 (Lacan, 1955a)。
在拉康著作中出现的其他重要的四元结构有L图式（SCHEMAL:带有四个结点），四种部分冲动和与之相应的四种不同对象，以及四大话语（每一话语皆有四个符号被指派给四个位置）。此外，拉康还列举出了四个“精神分析的基本概念”(Lacan,1964a),并且讲到“圣状”是避免使博洛米结(BORROMEAN KNOT)中的其他三个圆环(即实在界、象征界与想象界的三大秩序)分离开来的第四个圆环。
(quaternaire) A quaternary is a structure which comprises four elements. Although Lacan's rejection of dualistic schemas in favour of an emphasis on the triangularstructure of the symbolic involves a predominance of triadic schemes in his work (seeDUAL RELATION), Lacan also insists on the importance of fourfold schemes: 'Aquadripartite structure has, since the introduction of the unconscious, always beenrequired in the construction of a subjective ordering' (Ec, 774).
The emphasis on the quaternary first comes to the fore in Lacan's work in the early1950s, and is perhaps due to the influence of Claude Levi-Strauss, whose work on thestructure of the avunculate shows that the basic unit of kinship always involves aminimum of four terms (Levi-Strauss, 1945). Thus, in a 1953 paper which deals with theneurotic's 'individual myth' (another reference to Levi-Strauss), Lacan remarks that'there is within the neurotic a quartet situation' (Lacan, 1953b:231), and adds that thisquartet can demonstrate the particularities of each case of neurosis more rigorously thanthe traditional triangular thematisation of the Oedipus complex (Lacan, 1953b:232). Heconcludes that 'the whole oedipal schema needs to be re-examined' (Lacan, 1953b:235). Thus, in addition to the three elements of the Oedipus complex (mother, child, father), Lacan often speaks of a fourth element; sometimes he argues that this fourth element isDEATH (Lacan, 1953b: 237; S4,431), and at other times he argues that it is the PHALLUS (S3,319).
In 1955, Lacan goes on to compare psychoanalytic treatment to bridge,'a game forfour players' (E, 139; see E, 229-30). In the same year, he describes a quaternary madeup of a triadic structure plus a fourth element (the LETTER) which circulates amongthese three elements (Lacan, 1955a).
Other important quaternary structures which appear in Lacan's work are SCHEMA L (which has four nodes), the four partial drives and their four corresponding part-objects, and the four discourses (each of which has four symbols assigned to four places). Lacanalso enumerates four 'fundamental concepts of psychoanalysis' (Lacan, 1964a), andspeaks of the sinthome as a fourth ring which prevents the other three rings in theBORROMEAN KNOT (the three orders of the real, the symbolic and the imaginary) from becoming separated.