Anatomical Basis and Effects of Medial and Lateral Medullary Syndromes

Lateral Medullary Syndrome: Vascular Causes, Affected Structures, and Pathophysiology

Lateral medullary syndrome (also known as Wallenberg's syndrome) arises from an infarction in the lateral medulla due to disruption of the posterior inferior cerebellar artery (PICA) or vertebral artery. This neurological disorder results in deficits affecting sensory and motor functions.

Vascular Causes

• Occlusion of the PICA or vertebral artery
• Ischemia-induced damage to brainstem structures

Affected Structures

• Spinal nucleus of the trigeminal nerve (causing ipsilateral facial sensory loss)
• Spinothalamic tract (leading to contralateral loss of pain and temperature sensation)
• Inferior cerebellar peduncle (resulting in ataxia)
• Nucleus ambiguus (causing dysphagia, dysarthria, and vocal cord paralysis)

Pathophysiology

The disruption in blood supply leads to neuronal dysfunction, resulting in characteristic symptoms such as Horner's syndrome, ataxia, and sensory deficits. Timely diagnosis and intervention are crucial for preventing complications.