Posterior interosseous syndrome is a neuropathy of the deep muscular branch of the radial nerve. Just distal to the elbow the posterior interosseous nerve can be compressed by tumors, ganglia, or fibrous of joint capsule, or by a spontaneous compression that may occur at the point of passage through the arcade.

We reports the 4 cases of posterior interosseous syndrome which was not related to trauma.

Keywords :Posterior interosseous syndrome, Deep branch of radial nerve, Spontaneous compression