oblongata

The medulla oblongata, often called the oblongata, is the caudal portion of the brainstem. It connects the pons to the spinal cord and sits in the posterior cranial fossa, just above the foramen magnum. It contains nuclei for several cranial nerves (notably IX through XII) and houses autonomic and somatic motor centers, serving as a major conduit for descending motor and ascending sensory pathways between the brain and spinal cord.

On the ventral surface the medulla shows the pyramids, where corticospinal fibers descend and cross in the decussation of the pyramids. Lateral to the pyramids lie the olives and the inferior olivary nuclei. The dorsal surface bears the gracile and cuneate tubercles, corresponding to the gracile and cuneate nuclei of the dorsal columns. The floor of the fourth ventricle forms its posterior boundary, separating it from the cerebellum.

Functionally, the medulla houses essential autonomic centers for cardiovascular and respiratory control, including the cardiac and vasomotor centers and the dorsal motor nucleus of the vagus. It contains several cranial nerve nuclei, such as the nucleus ambiguus and the hypoglossal nucleus, and participates in visceral sensory pathways via the solitary nucleus. It acts as a critical relay and processing center, coordinating reflexes such as coughing, sneezing, swallowing, and vomiting, and it serves as a conduit for major neural tracts between the brain and spinal cord, including corticospinal, spinothalamic, and cerebellar pathways.

Developmentally, the medulla oblongata arises from the embryonic myelencephalon. The term oblongata derives from Latin, meaning elongated.