The Fascial Layers Attached to the Skull Base: A Cadaveric Study.

OBJECTIVE: A profound understanding of the relationship between the deep cervical fasciae and the skull base is essential for skull base surgery. To our knowledge, there has been little research on the relationship between the deep cervical fasciae and inferior surface of the skull base; thus, this study aims to examine the fascial network of the skull base.

METHODS: Two cadaveric heads are dissected to reveal the fascial network of the skull base and 19 sides of cadaveric heads were used to reveal an anatomical variant of the pterygospinous and pterygoalar ligaments/muscles.

RESULTS: The interpterygoid fascia is attached to the skull base along the sphenopetrosal fissure and tympanosquamous suture. The tensor vascular styloid fascia extends from the inferior border of the tensor veli palatini and covers the tympanic bone and styloid apparatus laterally. The pharyngobasilar fascia attaches to the pharyngeal tubercle on the inferior surface of the basilar part of the occipital bone and petro-occipital synchondrosis. In the middle of the clivus, we found thick fibrocartilaginous tissue and the prevertebral fascia fused to this area. Fascia of the longus capitis, the tensor-vascular styloid fascia, and stylopharyngeal fascia extend laterally and form the complex fascial network around the internal jugular vein and the internal carotid artery. The carotid sheath attaches anteriorly to the vaginal process and posteriorly to the fibrocartilaginous tissue around the jugular foramen and carotid canal.

CONCLUSIONS: This study comprehensively exposes the fascial network of the skull base. Our cadaveric dissection findings support those from previous imaging-anatomical studies. Precise knowledge of these fascial layers is essential for accurate diagnosis and understanding the spread of disease, as well as helping skull base surgeons safely perform challenging procedures.