Do Grossly Identifiable Ganglia Lie Along the Spinal Accessory Nerve? A Gross and Histologic Study with Potential Neurosurgical Significance

Antegrade Auriculotemporal-Inferior Alveolar Nerve Communication in the Infratemporal Fossa

Communications between cranial nerves or their branches have been described previously. The exact functional significance of some of these neural communications remains to be fully understood. This paper reports a unique communication between the auriculotemporal and inferior alveolar nerves within the infratemporal fossa. The histological examination indicates an antegrade connection from the inferior alveolar nerve to the auriculotemporal nerve, which could potentially be implicated in referred pain from the anatomical territory of one nerve to the other.

Benign Enhancing Foramen Magnum Lesions

Benign enhancing foramen magnum lesions have been previously described as T2-hyperintense small, enhancing lesions located posterior to the intradural vertebral artery. We present the first case with pathologic correlation. These lesions are fibrotic nodules adhering to the spinal accessory nerve. While they can enlarge with time on subsequent examinations, on the basis of the imaging characteristics and location, they do not necessitate surgical resection.

Evaluation of a high-signal lesion posterior to the intracranial vertebral artery using 3D balanced fast-field echo imaging

Previous reports have identified a small, benign, high-signal lesion (HSL) posterior to the intracranial vertebral artery and associated with the ipsilateral spinal accessory nerve (SAN) using 3D fluid-attenuated inversion recovery (3D FLAIR) imaging as an emerging new entity. To elucidate the relationship between HSLs and SAN, 76 patients with 86 HSLs were evaluated using 3D FLAIR and 3D balanced fast-field echo (3D bFFE imaging). All HSLs showed contact with ipsilateral SAN on both the sequences. 3D bFFE imaging clearly distinguished between the two structures unlike 3D FLAIR. Moreover, SAN was surrounded by HSLs on 3D bFFE images, which may be a characteristic of this entity.

Benign Enhancing Foramen Magnum Lesions: Clinical Report of a Newly Recognized Entity

Intradural extramedullary foramen magnum enhancing lesions may be due to meningioma, nerve sheath tumor, aneurysm, or meningeal disease. In this clinical report of 14 patients, we describe a novel imaging finding within the foramen magnum that simulates disease. The lesion is hyperintense on 3D-FLAIR and enhances on 3D gradient-echo sequences but is not seen on 2D-TSE T2WI. It occurs at a characteristic location related to the posterior aspect of the intradural vertebral artery just distal to the dural penetration. Stability of this lesion was demonstrated in those patients who underwent follow-up imaging. Recognition of this apparently benign lesion may prevent unnecessary patient anxiety and repeat imaging.

Histologic confirmation of neuronal cell bodies along the spinal accessory nerve

INTRODUCTION

Most sources conclude that the spinal accessory nerve (SAN) is a purely motor nerve. There are some reports that suggest a sensory component, although the exact nature of such sensory fibers has yet to be elucidated. With such discrepancies in the literature and with well-established pain syndromes of unknown etiology following SAN injury, the authors performed the present study to better clarify this anatomy.

MATERIALS AND METHODS

The entire accessory nerve was harvested from 10 adult cadavers. Samples were then submitted for immunohistochemical analyses.

RESULTS

Occasional microganglia cells were identified along the SAN in all specimens. These ganglia were most numerous along the intracranial segment of the SAN, but none was found along the cranial rootlets of the accessory nerve.

CONCLUSIONS

Neuronal cell bodies were identified along the course of the SAN in human cadavers. Although the function is not certain, such cells have been found in other animals to be nocioceptive in nature. Pending further study, these cells may be found to be involved in enigmatic pain syndromes thought to arise in the sternocleidomastoid and trapezius muscles.