Radiologic evaluation of the normal and diseased posterior cervical space.

The posterior cervical space seen on cross-sectional imaging of the neck constitutes most of the posterior triangle seen on clinical examination. Although triangular anatomy relates best to the surface perspective of the clinician, a spatial approach to anatomy works better for the radiologist viewing axial images. The posterior cervical space is defined as the area in the posterolateral portion of the neck from the skull base to the clavicles deep to the sternomastoid and trapezius muscles but superficial to the prevertebral space. Its principal contents are fat, the spinal accessory nerve, and lymph nodes. We analyzed CT and MR images and clinical records of 63 patients known or suspected to have disease of the posterior cervical space to determine the imaging features that mark a lesion as originating in the posterior cervical space and the spectrum of diseases that arise there. Of the 63 patients in the study, four had clinical pseudomasses, nine had congenital lesions, 10 had inflammatory disease, six had benign tumors, and 34 had malignant tumors. A typical mass lesion of the posterior cervical space was centered within the fat of the space, between the deep and superficial layers of the deep cervical fascia. Characteristic displacements caused by a mass in the posterior cervical space included anteromedial displacement of the carotid space and posteromedial displacement of the prevertebral space. Our study shows that the differential diagnosis of lesions of the posterior cervical space reflects the normal contents of the space, and that diagnosis can thereby be predicted from knowledge of the normal anatomy and contents of the space.