Clinical Images: Acute calcific tendinitis of the longus colli muscleThe patient, a 32-year-old man, presented with a 1-month history of severe pain in the posterior neck and shoulder without evidence of any trigger. He also experienced mild odynophagia while drinking water. Physical examination revealed a markedly reduced active range of cervical motion. No fever was noted, and laboratory tests revealed a normal complete blood cell count, erythrocyte sedimentation rate, and C-reactive protein level. Sagittal T2-weighted magnetic resonance imaging of the cervical spine revealed a lowintensity nodular lesion around the C2 body (arrow in A); computed tomography (CT) of the neck revealed a large, oval calcification, inferior to the anterior arch of the C1 body (arrows in B and C). Thus, the patient was diagnosed as having calcific tendinitis of the longus colli muscle. The symptoms quickly resolved following therapy with oral nonsteroidal antiinflammatory drugs and colchicine. Lateral cervical radiographs taken after 4 months confirmed the complete resolution of the calcification (arrows in D and E). Acute calcific tendinitis of the longus colli muscle (or retropharyngeal tendinitis) is an aseptic inflammatory process caused by calcium hydroxyapatite crystal deposition in the longus colli tendon. It is typically observed between ages 30 and 60 years (1), and presents as neck pain, limited neck movement, and dysphagia or odynophagia (2). During diagnosis, this condition should be differentiated from retropharyngeal abscess, cervical osteomyelitis, spondylodiscitis, retro-odontoid pseudotumor, crowned dens syndrome, and meningitis. CT is the most sensitive diagnostic imaging technique and enables the identification of the amorphous calcification in the proximal fibers of the longus colli-a specific characteristic of this disease (3).