Home > Medulla oblongata

The medulla is often thought of as being in two parts, an open part (close to the pons), and a closed part (further down towards the spinal cord). The 'opening' referred to is on the dorsal side of the medulla, and forms part of the fourth ventricle of the brain.

Running down the ventral aspect of the medulla are the pyramids which contain corticospinal fibres. On the open medulla, there is a slight bulge just behind the pyramids called the olive or olivary nuclei . Cranial nerve XII (the hypoglossal nerve) emerges between these two structures. Cranial nerves IX and X ( glossopharyngeal and vagus nerves) also emerge from the medulla.

1 Function of the medulla oblongata

1. To control automatic functions (such as breathing and heartbeat)
2. To relay nerve messages from the brain to the spinal cord
3. Processing of inter-aural time differences for sound localization (olivary nuclei)

2 Cross-sections through the medulla

3 Blood supply

Blood to the medulla is supplied by a number of arteries.

• Direct branches of the vertebral artery
• Posterior inferior cerebellar artery (PICA)
• Anterior spinal artery

The anterior spinal artery supplies the whole medial part of the medulla oblongata. A blockage (such as in a stroke) will injure the pyramidal tract, medial lemniscusThe medial lemniscus also known as Reil's band or Reil's ribbon is a pathway in the brainstem, that carries sensory information from the gracile and cuneate nuclei to the thalamus. After neurons carrying proprioceptive or touch information synapse at the and the hypoglossal nucleus. This causes a syndrome called medial medullary syndromeMedial medullary syndrome (also known as Dejerine syndrome is a set of clinical features resulting from an infarction in the brainstem. The vessel usually involved is the anterior spinal artery which supplies the medial part of the medulla oblongata..

The posterior inferior cerebellar artery, a major branch of the vertebral artery, supplies the posterolateral part of the medulla, where the main sensory tracts run and synapsenerve cells to communicate with one another through axons and dendrites, converting electrical signals into chemical ones. For the technology festival, see Synapse Festival. Synapses are specialized junctions through which cells of the nervous system sign. (As the name implies, it also supplies some of the cerebellum.)

The vertebral artery supplies an area between the other two main arteries, including the nucleus solitarius and other sensory nuclei and fibres. Lateral medullary syndromeLateral medullary syndrome (also called Wallenberg's syndrome is a disease in which the patient has difficulty with swallowing or speaking or both owing to one or more patches of dead tissue (known as an infarct caused by interrupted blood supply to parts can be caused by occlusion of either the PICA or the vertebral arteries.