Medulla oblongata

Function

The medulla is the brainstem's tapering floor, where the fourth ventricle narrows into the central canal. It is the body's autonomic control room: the cardiovascular centre sets heart rate and vascular tone, the respiratory centre sets rhythm and depth, and the vomiting, coughing, swallowing and sneezing reflexes live here.

Pyramids carry corticospinal fibres that decussate at its lower end — the reason each hemisphere moves the opposite body. Its nuclei receive IX, X, XI and XII; the gracile and cuneate nuclei on its dorsal face are where the body's fine-touch and position sense first synapse.

Blood supply

Vertebral and anterior spinal arteries.

Nerve supply

Cranial nerves IX–XII; vagal autonomic outflow to heart, lungs and gut.

Clinical relevance

Wallenberg syndrome

Lateral medullary infarction (PICA) causes vertigo, ipsilateral facial numbness with contralateral body numbness, hoarseness and hiccups.

Brainstem death

Medullary failure abolishes spontaneous breathing — the basis of brainstem-death criteria in many countries.