'brainstem' is a loose term that sometimes refers to the ventral parts o the brain except for any part of the telencephalon - sometimes it includes the diencephalon or subpallial telencephalon structures (ISBN:0471888893). Here we use it in a more restriced sense, to include only the medulla oblongata, pons (when present) and the midbrain tegmentum (following the ZFA definitions).

http://upload.wikimedia.org/wikipedia/commons/b/b7/Gray719.png

Multi-tissue structure that has as its parts the medulla oblongata of the hindbrain and the tegmentum of the midbrain[ZFA,adopted][ZFA:0001707]., the stalk-like part of the brain that comprises the midbrain (aka mesencephalon), the pons (aka pons Varolii), and the medulla oblongata, and connects the cerebral hemispheres with the cervical spinal cord[MP], Multi-tissue structure that has as its parts the medulla oblongata of the hindbrain and the tegmentum of the midbrain.[TAO]

uberon

lamina medullaris incompleta pallidi, lamella pallidi incompleta, accessory medullary lamina of pallidum, lamina medullaris accessoria, truncus encephalicus, lamina pallidi incompleta

UBERON:0002298

• cochlear nucleus
• pons

• medulla oblongata
• midbrain tegmentum
• reticular formation
• brainstem nucleus
• pons
• brainstem white matter