Entrapment of the posterior interosseous nerve at the arcade of Frohse with sonographic, magnetic resonance imaging, and intraoperative confirmation.

ntrapment of the radial nerve, specifically the deep branch of the radial nerve (DBRN) in the arcade of Frohse, was first described in 1963.1 Prolonged entrapment may lead to a constellation of symptoms described in posterior interosseous nerve (PIN) paralysis.2 Reported attempts at diagnosis using imaging have mostly involved magnetic resonance imaging (MRI), with a limited number of studies characterizing the utility of sonography. Confirmation of entrapment via MRI, sonography, and gross specimens obtained intraoperatively during surgical decompression is presented.