Pons

Function

The pons — the 'bridge' — is the brainstem's mid-storey. Its ventral basis is a massive relay station shuttling cerebro-cerebellar traffic through the middle cerebellar peduncles; behind it, the tegmentum carries ascending lemnisci and houses the cranial nerve nuclei of V, VI, VII and VIII.

The pontine respiratory group and pneumotaxic centre fine-tune breathing rhythm here, while corticospinal fibres compact into bundles destined for the limbs.

Blood supply

Paramedian and circumferential branches of the basilar artery.

Nerve supply

Cranial nuclei V–VIII; reticular formation.

Clinical relevance

Locked-in syndrome

Basilar thrombosis disconnecting the corticobulbar and corticospinal tracts leaves a conscious mind in a still body — blinking remains.

Central pontine myelinolysis

Over-rapid correction of low sodium strips pontine myelin — an iatrogenic catastrophe of fluid balance.