“Lacan calls the specular image “orthopaedic” as it leads the child to anticipate the overcoming of its “real specific prematurity of birth”. The vision of the body as integrated and contained, in opposition to the child’s actual experience of motor incapacity and the sense of its body as fragmented, induces a movement from “insufficiency to anticipation”. In other words, the mirror image initiates and then aids, like a crutch, the process of the formation of an integrated sense of self.
In the Mirror stage a misunderstanding – “méconnaissance” – constitutes the Ego—the ‘moi’ becomes alienated from itself through the introduction of an imaginary dimension to the subject. It must be said that the mirror stage also has a significant symbolic dimension. The Symbolic order is present in the figure of the adult who is carrying the infant: the moment after the subject has jubilantly assumed his image as his own, he turns his head towards this adult who represents the big Other, as if to call on him to ratify this image.” from an article on le stade du miroir in Lacanian theory, posted on Wikipedia 2010.