In the anatomy of humans and of many other vertebrates, the brainstem (or brain stem) is the posterior part of the brain, adjoining and structurally continuous with the spinal cord. In humans it is usually described as including the medulla oblongata (myelencephalon), pons (part of metencephalon), and midbrain (mesencephalon).Less frequently, parts of the diencephalon are included. The brainstem provides the main motor and sensory innervation to the face and neck via the cranial nerves.