Fascial layers encountered in the lateral skull base region: A cadaveric and radiological analysis

BackgroundIn our experience, the anterior carotid sheath forms an important plane of dissection when excising temporal bone region cancers. However, its anatomical composition, relationships, and radiological appearance remains unclear. MethodsEight sides of cadaveric heads were dissected. Anatomical findings were correlated with a high-resolution baseline T1 MRI. ResultsThe anterior carotid sheath was formed by the tensor-vascular-styloid fascia, stylopharyngeal fascia, buccopharyngeal fascia (BPF), and longus capitis fascia (LCF), and appeared as a hypointense line on MRI. Not previously described, the glossopharyngeal nerve pierced the sheath 9.0 mm (SD 2.1 mm) below the skull base and traveled through its LCF and BPF layers to exit near the pharynx. ConclusionMultiple fascial layers formed the anterior carotid sheath at the skull base, and this was radiologically identifiable. Further studies are required to validate findings and investigate the role this fascial plane has in forming an effective barrier to spread of malignancy.

Automated summary

In our study, we found that the anterior carotid sheath, consisting of several fascial layers, plays a vital role in the dissection of temporal bone region cancers. This sheath can be seen on high-resolution MRI as a hypointense line. Additionally, we discovered that the glossopharyngeal nerve pierces through the sheath and exits near the pharynx. Further research is needed to confirm these findings and understand the role of the anterior carotid sheath in preventing the spread of malignancy.