Synonyms
Medulla oblongata, bulb medullae spinalis
Definition
The medulla oblongata is part of the central nervous system (CNS). It is the lowest (caudal) part of the brain. The medulla oblongata is counted together with the bridge (pons) and the midbrain (mesencephalon) as part of the brain stem (truncus cerebri).
The medulla oblongata contains nerve nuclei and pathways that control vital processes such as breathing. In addition, some of the 12 cranial nerves are located here. The medulla oblongata connects to the spinal cord in an upward (cranial) direction.
It begins at the exit of the first spinal nerve. Further cranially it borders on the bridge (Pons). It is thus the anatomically lowest part of the brain.
Together with the bridge and the cerebellum, it belongs to the rhombic brain (rhombencephalon). Anatomically, it is divided into three parts: The tegmentum (hood), the pyramids and the olives or olive stones. The tegmentum is located at the back (dorsal) and is the origin of numerous nerve cells, i.e. nerve core areas are located here.
The pyramids lie on both sides of the midline on the front side of the medulla oblongata. They are the part of the medulla oblongata in which the pyramidal tract runs along. The pyramidal tract is responsible for much of the voluntary movement.
A lesion of the pyramidal tract leads to paralysis in the affected body area. In the lower part of the pyramids about 80% of the pyramidal tract crosses from one side to the other. This means that the pathways from the right side of the brain cross to the left side of the body and those from the left side of the brain cross to the right side of the body.
This is the reason why a stroke in the area of the right hemisphere of the brain often results in a significant restriction of the mobility of the left hemisphere of the body, this is called hemiparesis. The olives are protrusions on both sides of the pyramids slightly to the side. They in turn contain nerve cell nuclei.