a b s t r a c tIn the present paper, the linear Cosserat elasticity involving the grid framework model for micro-rotations as boundary condition or side-condition has been taken into account. Theassumption or so called case 4, altogether case 1 (a = b = 0 and c ¼ lL 2 c ), case 2 a ¼ 0 andare examined by means of some numerical experiments for torsion test with a circular bar. The presence of m 33 (stress moment in z direction) on the top of specimen is confirmed numerically and analytically via a missing term R @Xt ðr  t ðnÞ Þ Á d/ dS . By considering this term, m 33 is non-zero, whereas, the Dirichlet boundary condition for displacements on the top of bar is used to apply the torque (M T ). The outcomes reveal that the case 4 as well as other cases is still bounded. This property is found out for curvature stiffness as well. These cases are presented in Torque-Log (L c ) diagram. In this diagram, two non-size affected zones (zones I and III) and one size affected zone would be inferred. By taking advantage of this curve, we can probably consider Cosserat theory as a multi-scale tool and some outlooks for a fresh experimental departure are discussed.