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 (V); - a distal base element , configured to connect to a prosthesis , the prosthesis having a second longitudinal axis coinciding with an axis orthogonal (A) 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 (P) substantially orthogonal to the first longitudinal axis (V) and to the second longitudinal axis (V) 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 (V) of the prosthetic socket and the second longitudinal axis (A) 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 (V); - a distal base element , configured to connect to a prosthesis , the prosthesis having a second longitudinal axis coinciding with an axis orthogonal (A) 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 (P) substantially orthogonal to the first longitudinal axis (V) and to the second longitudinal axis (V) 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 (V) of the prosthetic socket and the second longitudinal axis (A) 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 . <EOS>