ventral surface of the brain stem Medulla oblongata Pyramid锥体: contain pyramidal tract (corticospinal tract) Decussation of pyramid锥体交叉 formed by crossing fibers of corticos pinal tract oive橄榄: overlying inferior olivary nucleus下橄榄核 hypoglossal nerve舌下神经 emerge from anterolateral sulcus Glossopharyngeal n. emerge from vagus n. retroolivary sulcus accessory n 橄榄后沟ventral surface of the brain stem Pyramid 锥体: contain pyramidal tract (corticospinal tract) Decussation of pyramid 锥体交叉 formed by crossing fibers of corticospinal tract emerge from retroolivary sulcus 橄榄后沟 Medulla oblongata hypoglossal nerve 舌下神经 emerge from anterolateral sulcus Glossopharyngeal n. vagus n. accessory n. Olive 橄榄: overlying inferior olivary nucleus下橄榄核