Clinical meaning
Trigeminal neuralgia (TN), also called tic douloureux, is a chronic pain condition affecting the trigeminal nerve (CN V) that causes sudden, severe, shock-like facial pain episodes lasting seconds to two minutes. It is often described as one of the most painful conditions known to medicine. The trigeminal nerve has three branches: V1 (ophthalmic) supplies the forehead and upper face, V2 (maxillary) supplies the cheek and upper jaw, and V3 (mandibular) supplies the lower jaw and chin. The most common branches affected in TN are V2 and V3, producing pain in the cheek, jaw, teeth, gums, and lips. V1 is involved in less than 5% of cases. The most common cause (80-90%) is vascular compression of the trigeminal nerve root entry zone by an aberrant arterial loop (usually the superior cerebellar artery). The pulsating artery compresses and irritates the nerve, causing focal demyelination. When the demyelinated fibers are exposed, normal sensory signals (light touch from washing the face, eating, brushing teeth) can trigger abnormal high-frequency discharges that spread to adjacent pain fibers, producing the characteristic lancinating pain. TN episodes are triggered...