Septic arthritis of the C1-C2 lateral facet joint and torticollis: pseudo-Grisel's syndrome. We present the case of a 76-year-old man who experienced the sudden development of fever, rightsided neck pain and stiffness, and torticollis. A soft tissue mass was noted on the right side of his neck, but his head was tilted to the left. Computed tomography scans (with reformatted sagittal and coronal images) of the patient's cervical spine revealed destructive changes of the right lateral masses of C1 and C2 and the clivus, and a well-delineated peridontoid soft tissue mass (confirmed by magnetic resonance imaging). After the second episode of right-sided hemiparesis, he underwent transoral surgical exploration, with anterior decompression and odontoidectomy. Histologic examination of the surgical material revealed granulation tissue, fibrosis, and chronic inflammation, consistent with abscess formation with invasion and compression of the spinal cord and bone. This case suggests that nonreducible rotational head tilt to the side opposite the side of lateral mass collapse should raise the suspicion of a possible infection. 