prepontine

Prepontine is a term used in anatomy to describe structures located in front of the pons, a major component of the brainstem. In neuroanatomy it is most often encountered in reference to the prepontine cistern, a subarachnoid space in the posterior cranial fossa.

The prepontine cistern lies anterior to the pontine ventral surface and behind the clivus. It forms part of the interconnected cisternal system that surrounds the brainstem and communicates laterally with the cerebellopontine angle cistern. The cistern contains cerebrospinal fluid and several important vascular and neural structures, most notably the basilar artery and its pontine branches. It also contains the cisternal segments of cranial nerves, particularly the abducens nerve, which traverses this space as it courses toward the cavernous sinus and orbit.

Clinically, the prepontine region is relevant because lesions in this area—such as clival or ventral brainstem tumors, chordomas, meningiomas, or aneurysms of the basilar artery or nearby vessels—can affect ventral pons function or compress the adjacent cranial nerves. Imaging studies, including MRI and CT angiography, frequently assess the prepontine cistern to evaluate pathology at the skull base and ventral brainstem. Surgical approaches to lesions in this region, such as extended endoscopic endonasal routes to the clivus, consider the prepontine space to minimize risk to critical structures.

In summary, prepontine denotes anterior relations to the pons, with the prepontine cistern being a key container of CSF, the basilar artery and its branches, and the cisternal portions of relevant cranial nerves.