This report analyzes the most frequently observed migration paths of disk fragments in 47 patients who had extruded or sequestered disks. Observations are based principally on magnetic resonance (MR) images. When disk fragments moved in a superior (42%) or inferior (40%) direction from the donor disk, the displaced disk components were most frequently (94%) dislodged into the right or left half of the anterior epidural space (AES) and rarely straddled the midline. To explain this phenomenon, the authors investigated the anatomy of the AES by dissecting four cadaver specimens and reviewing 300 MR images of the spine. They conclude that the migrating path of a disk fragment is determined by the anatomy of the AES, a fairly well-defined space delimited posteriorly by the posterior longitudinal ligament and by membranes laterally attached to it. It consists of two compartments separated by a sagitally aligned septum. During migration, sequestered disk fragments usually stay in these compartments.

The retropharyngeal and cervical lymph-node-bearing areas in 30 patients were examined with computed tomography (CT) to determine the range of normal variation in these nodal groups. The data agree with those in the pathologic, anatomic, and surgical literature, and indicate that CT can very precisely determine the size and gross morphology of normal nodes in the retropharyngeal region and the neck. This should have important applications in the management of patients with head and neck cancer.

A review was made of the clinical records and radiographic examinations of 38 patients with neck lesions clinically suspected of being branchial cleft anomalies. The impact of computed tomography in this sometimes confusing clinical picture was assessed and CT criteria for diagnosing branchial cleft anomalies (BCAs) and differentiating them from their mimics were identified. Seventeen branchial cleft anomalies (four of the first branchial cleft and 13 of the second branchial cleft) and 21 BCA mimics were evaluated. A definitive CT diagnosis of second branchial cleft cysts based on characteristic morphology, location, and displacement of surrounding structures was possible in 80% of cases. CT was found to be the best radiographic examination in making a definitive diagnosis of BCA if a neck mass was present. CT-derived information, by providing additional preoperative data on the extent and type of neck lesion, frequently altered the course of patient management.

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CT scans of 35 patients were obtained during rapid drip infusion of contrast material to determine the range of normal variation in the structures of the oropharynx and the floor of the mouth. Superficial structures such as the tonsillar pillars and lingual and faucial tonsils vary so much in appearance that they are not useful indicators in the detection of subtle lesions; in fact, they are potential sources of "pseudomasses." Asymmetric obliteration of the parapharyngeal space is useful for the detection of subtle lesions of the upper tonsillar fossae; however, confident diagnosis in regard to the lower oropharynx depends on visualization of a mass lesion or loss of the more constant planes in the floor of the mouth and the tongue base. CT findings added unique and valuable information in eight of 12 cases of carcinoma, confirmed the clinical impression of the extent of the lesion in four cases, and were potentially misleading in one case. CT is a valuable adjunct to the detection and staging of an oropharyngeal malignancy.