my·e·len·ceph·a·lon 
(mī′ə-lĕn-sĕfə-lŏn′)
(mī′ə-lĕn-sĕfə-lŏn′)n.
1. The posterior portion of the embryonic hindbrain, from which the medulla oblongata develops.
2. The medulla oblongata of the adult brain.
my′e·len·ce·phalic (-sə-fălĭk) adj.