PMC9708331_01
(a) Coronal reformatted CT image shows osteophytosis (arrow) of the atlanto-occipital articulation on the right. The osteophyte arising from the occipital condyle narrows the hypoglossal canal (asterisks). (b) Axial CT showing osteophyte in the right hypoglossal canal. (c) Sagittal CT showing osteophyte in the right hypoglossal canal.
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fig1
After reviewing the head CT and MRI with neuroradiology and including clear clinical information, degenerative osteophytes were seen projecting from the right atlanto-occipital joint laterally to the adjacent right carotid space, best seen on the CT (Figures 1(a)-1(c)).
Axial steady-state free procession MR image through the skull base shows the hypoglossal nerve (arrowhead) passing through the hypoglossal canal (arrow). The osteophyte (dashed oval) lies just anterior to the hypoglossal canal, along the expected path of the hypoglossal nerve.
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fig2
The osteophyte could be seen at the exit of the right hypoglossal canal on axial MRI images but it was much more difficult to visualize (Figure 2).
Axial CT image showing postoperative appearance. The hypoglossal canal was decompressed laterally via partial mastoidectomy, high cervical dissection, and partial resection of the occipital condyle. Metallic plating (arrow) covers the postoperative site.
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fig3
Postoperative CT is shown in Figure 3.