What does myelencephalon mean?
The myelencephalon is the posterior part of the embryonic brain and the final secondary vesicle of the hindbrain. Together with the metencephalon, it develops from the rhombencephalon, or primitive hindbrain. Its principal derivative is the medulla oblongata, the lower portion of the brainstem that helps regulate breathing, heart rate, blood pressure, swallowing, and other automatic functions. In embryological descriptions, the myelencephalon is therefore a transient developmental structure rather than simply another name for the adult brainstem. Some anatomical references also use it for the corresponding region of the mature brain. The term is chiefly encountered in embryology, neuroscience, and comparative anatomy, where precision about both origin and adult structure matters. Understanding it clarifies how the brain's major divisions form during development and how the brainstem emerges from the primitive hindbrain.
nounThe myelencephalon is the most posterior secondary brain vesicle, developing from the rhombencephalon and giving rise to the medulla oblongata. In some adult anatomical contexts, it refers to the corresponding region of the hindbrain.
- The posterior secondary vesicle of the embryonic brain that develops into the medulla oblongata.
- The corresponding region of the adult hindbrain, especially the medulla oblongata.
"During embryonic development, the myelencephalon gives rise to structures that control vital autonomic functions."
"The myelencephalon begins to differentiate early in the development of the human brain."
"Damage to the myelencephalon region can affect breathing and cardiovascular control."
The plural is rarely needed in ordinary writing but follows the anatomical Latin plural convention.
"The myelencephala of the two embryos were compared during the study."
Before it becomes the medulla, the myelencephalon is the hindbrain's final embryonic chamber.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does myelencephalon come from?
The word combines the combining form myelo-, derived from Greek myelos, "marrow," with enkephalon, from Greek enkephalos, "brain." The myelo- element has a historical association with the marrow and spinal cord, rather than referring literally to the substance of the developing brain. In modern anatomical terminology, the compound denotes the posterior brain vesicle that becomes the medulla oblongata.
Related word forms
How myelencephalon is actually used
The term is most common in embryology and comparative neuroanatomy. It is more technical than the everyday term "brainstem," and its adult anatomical use is less frequent than its developmental use.
Easily confused with myelencephalon
The myelencephalon is the embryonic brain vesicle that develops into the medulla oblongata, whereas the medulla oblongata names the mature anatomical structure.
The encephalon means the brain as a whole, while the myelencephalon identifies a specific hindbrain region.