Three complementary views of the peripheral nervous system are: anatomical—its structures such as cranial and spinal nerves, roots, plexuses and ganglia; functional—pathways for sensory (afferent), motor (efferent) and autonomic (sympathetic/parasympathetic) signaling; and clinical—patterns of disease and injury (peripheral neuropathies, radiculopathies, neuromuscular junction disorders and autonomic dysfunction) guiding diagnosis and treatment.

A PNS axial, coronal, sagittal CT scan is a computed tomography study of the paranasal sinuses that acquires images in three planes: axial (horizontal), coronal (frontal) and sagittal (side). This multiplanar imaging shows sinus air spaces, mucosa, bone and adjacent structures, helping diagnose sinusitis, polyps, tumors, fractures and anatomic variations and guiding surgical planning. It is fast, noninvasive and more detailed than plain X‑rays.

Axial and coronal CT differ by imaging plane. Axial (transverse) images are taken horizontally, producing cross-sectional slices from top to bottom useful for brain, chest, and abdominal detail. Coronal images are vertical slices oriented front-to-back, showing relationships between anterior and posterior structures—helpful for sinuses, facial bones, and spinal alignment. Both can be reformatted from the same scan.

Another name for the PNS view is a sinus X‑ray, often called a Waters' (occipitomental) view. This radiographic projection visualizes the paranasal sinuses—particularly the maxillary sinuses—and is used to detect sinusitis, fluid levels, bony fractures, or other sinus pathology. It may be ordered when patients have facial pain, nasal discharge, or trauma.

Position the patient upright facing the image receptor and remove jewelry. For the Waters (paranasal sinuses) view, extend the neck so the mentomeatal line is about 37° to the receptor, rest the chin on the cassette, and keep the nose ~1–2 cm from it. Center the central ray at the acanthion, have the patient suspend respiration, and make the exposure. An open‑mouth variant shows the sphenoid.

The best plain radiographic view for the frontal sinuses is the PA axial (Caldwell) projection—an occipitofrontal view with about 15° caudal angulation of the central ray. It projects the frontal sinuses above the orbital roofs with minimal overlap. For detailed evaluation, especially suspected fractures or chronic disease, CT scanning remains the gold standard.