Generalized Extension of Referred Trigeminal Pain due to Greater Occipital Nerve Entrapment

Figure 2

MRI images of the greater occipital nerve (GON). (a) Sagittal (A) and coronal (B) MR images of the right GON (white arrow) in the current case. The left image represents a sagittal T2-weighted image (t2_de3d_we,_iso 0.7 mm, MPR, Magnetom Terra, Siemens, Germany) of the right GON taken along the distal portion path within the trapezial tunnel. The image on the right is a coronal MR image (t2_de3d_we, iso 0.7 mm, MPR) showing the course of the right and left (white arrowhead) GONs within the trapezial tunnel. SsCM; semispinalis capitis muscle. (b) Sagittal (A) and coronal (B) MR images of the right GON (white arrow) taken with the same MR sequence (t2_de3d_we,_iso 0.7 mm, MPR) in a patient suffering from right trigeminal neuralgia. This is presented for comparison with images from patients with GON entrapment. The image on the right is a coronal MR image (t2_de3d_we, iso 0.7 mm, MPR) showing the course of the right and left (white arrowhead) GONs within the trapezial tunnel. This MRI image shows that it is still difficult to clearly diagnose GON entrapment even with high-resolution MRI. SsCM, semispinalis capitis muscle.

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