Such as an inverted cone, its lower boundary is connected with the spinal cord at the place parallel to the foramen magnum, the ventral side of the upper boundary is separated from the pons by a transverse groove, and the dorsal side forms the lower half of the rhomboid fossa.The shape of the medulla oblongata is similar to that of the spinal cordspinal cordAs the continuation of each sulcus fissure, there is a longitudinal bulge on the ventral side and on both sides of the anterior median fissure, called the pyramid, which is composed of fibers of the corticospinal tract.Below the cone, 70-90% of the fibers cross left and right, which is called cone crossing.There is another pair of oval protuberances on the outside of the cone, called the olive body, between which lies the anterolateral sulcus, from which the hypoglossal nerve root exits the brain.In the longitudinal groove outside the olive body, there are glossopharyngeal nerve, vagus nerve and accessory nerve roots coming out of the brain from top to bottom.On the dorsal side, there is a pair of projections on both sides of the posterior median sulcus, called the tubercle of the thin bundle (rod-shaped body), which is the expansion part of the thin bundle that continues upward, and there is the nucleus of the thin bundle on the deep side.There is another pair of projections on the lateral side of the tubercle of the thin bundle, called the tubercle of the cuneiform bundle, which is the expansion part of the upward continuation of the cuneiform bundle. There is a nucleus of the cuneiform bundle on its deep side.There is a pair of lower cerebellar peduncles or cord like bodies outside and above the wedge bundle node, which are thick fiber bundles and are composed of fibers entering the cerebellum.
The internal structure of the medulla oblongata is similar to that of the spinal cord, with fiber bundles connecting the spinal cord and the brain passing through, as well as motor nuclei and termination nuclei of four pairs of brain nerves, namely, glossopharyngeal, vagal, accessory, and sublingual.The relationship between gray matter and white matter in the medulla oblongata gradually changes from the spinal cord upward.First, pyramidal crossing appeared at the lower end of medulla oblongata, cutting off the anterior horn of gray matter;Secondly, in the upper part of the medulla oblongata atresia, there is a cross of the thalamus;The four central canals are open, and the central gray matter of the spinal cord forms the gray matter at the bottom of the fourth ventricle, which contains the brain nerve nucleus;Finally, the part between the gray matter at the bottom of the fourth ventricle and the inferior olivary nucleus is separated by longitudinal and transverse fibers, forming a reticular structure.
physiological function
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The main function of the medulla oblongata is to regulate visceral activities. Many basic centers necessary for maintaining life (such as breathing, circulation, digestion, etc.) are concentrated in the medulla oblongata. Once these parts are damaged, they often cause rapid death, so the medulla oblongata is called "life center".If the medulla oblongata remains intact, even if the upper part is injured, the respiratory, circulatory and other functions can still be temporarily maintained without immediate death.
Bilateral medial medullary infarction
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（1） Introduction:
The medulla oblongata is located at the bottom of the brain stem. Because its blood supply is more abundant than other parts of the brain stem, the incidence of infarction in the medulla oblongata is less than that in the pons and midbrain. The medulla oblongata infarction accounts for less than 5% of the posterior circulation infarction. The medial medulla oblongata infarction is mostly related to vertebral artery occlusion, while the bilateral medial medulla oblongata infarction is mostly caused by unilateral vertebral artery occlusion and vascular variation.
（2） Clinical manifestations:
Main symptoms and signs: weakness of limbs, choking on drinking water, dysphagia and dysarthria, abnormal deep and shallow sensation, hemiplegia, dyspnea and disturbance of consciousness.
（3） Imaging findings:
The plain magnetic resonance scan showed that the bilateral medulla oblongata had long T1 and T2 signals, and the diffusion weighted imaging showed high signal, with a characteristic "heart shape" appearance.
