In this paper, the set J′=H(Q₄,Jγ) of 4 by 4 matrices, with entries in a quaternion F-algebra Q, that are symmetric with respect to the canonical involution Jγ is studied. J′ is also the special Jordan matrix algebra and some results related to points and lines of the quaternion 3-space P(J′) defined by the algebra are introduced. Finally, by taking dual ring Q:= Q+Qε (ε∉Q, ε²=0) instead of Q, the obtained results are carried to a more general state.