Module of flexion-extension for an artificial articulation, comprising: - a proximal base element, configured to connect to a prosthetic socket, the prosthetic socket having a first longitudinal axis; - a distal base element, configured to connect to a prosthesis, the prosthesis having a second longitudinal axis coinciding with an axis orthogonal to said distal base element; - mechanical connection means of said proximal base element with said distal base element, configured in such a way as to allow rotation of said distal base element with respect to said proximal base element about a rotation axis substantially orthogonal to the first longitudinal axis and to the second longitudinal axis in such a way as to realize a movement of flexion/extension of the prosthesis with respect to the socket; - stressing means connected to said mechanical connection means and to respective elastic reaction means, said elastic reaction means being configured to exert a reaction force apt to counteract the said rotation of said distal base element, wherein when said mechanical connection means is not operated, said elastic reaction means is configured to maintain said proximal base element and said distal base element in a rest configuration, wherein the first longitudinal axis of the prosthetic socket and the second longitudinal axis of the prosthesis are aligned, in particular coincident, characterised in that, said mechanical connection means comprises at least one Scotch- Yoke mechanism configured to transform a rotary motion of said distal base element with respect to said proximal base element in a linear motion of said stressing means, the overall configuration of said module of flexion-extension being such that: when said mechanical connection means is operated by said rotation of said distal base element with respect to said proximal base element, said stressing means is linearly moved to elastically deform said elastic reaction means. - a proximal base element, configured to connect to a prosthetic socket, the prosthetic socket having a first longitudinal axis; - a distal base element, configured to connect to a prosthesis, the prosthesis having a second longitudinal axis coinciding with an axis orthogonal to said distal base element; - mechanical connection means of said proximal base element with said distal base element, configured in such a way as to allow rotation of said distal base element with respect to said proximal base element about a rotation axis substantially orthogonal to the first longitudinal axis and to the second longitudinal axis in such a way as to realize a movement of flexion/extension of the prosthesis with respect to the socket; - stressing means connected to said mechanical connection means and to respective elastic reaction means, said elastic reaction means being configured to exert a reaction force apt to counteract the said rotation of said distal base element, when said mechanical connection means is not operated, said elastic reaction means is configured to maintain said proximal base element and said distal base element in a rest configuration, wherein the first longitudinal axis of the prosthetic socket and the second longitudinal axis of the prosthesis are aligned, in particular coincident, characterised in that, said mechanical connection means comprises at least one Scotch- Yoke mechanism configured to transform a rotary motion of said distal base element with respect to said proximal base element in a linear motion of said stressing means, the overall configuration of said module of flexion-extension being such that: when said mechanical connection means is operated by said rotation of said distal base element with respect to said proximal base element, said stressing means is linearly moved to elastically deform said elastic reaction means.