Brainstem

Last revised by Raymond Chieng on 6 May 2023

The brainstem is the most caudal part of the brain. It adjoins, is structurally continuous with the spinal cord and consists of the:

The brainstem provides the main motor and sensory innervation to the face and neck via the cranial nerves. It also provides the connection of the cerebrum, basal ganglia, diencephalon, cerebellum and spinal cord. Additionally, there are other brainstem nuclei.

The brainstem also plays an important role in the regulation of cardiac and respiratory function. It also regulates the central nervous system and is pivotal in maintaining consciousness and regulating the sleep cycle.

Some taxonomies describe the brainstem as only containing the medulla oblongata and pons, whereas others include the midbrain.

Radiological features

Ultrasound

The brainstem structures can be seen by positioning the ultrasound probe against the squamous suture of the temporal bone or against the upper nuchal area using the foramen magnum as the window. Midbrain, pons, and medulla all appear hypoechoic on ultrasound. Hyperchoic brainstem may indicate pathology 7.

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Cases and figures

  • Figure 1: illustration - brainstem
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  • Figure 2: diagram - brainstem
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  • Figure 3: illustration - brainstem - sagittal image
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  • Figure 4: diagram - brainstem
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  • Figure 5: diagram - brainstem
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  • Figure 6: embryology
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  • Figure 7: arterial vascular territories (illustration)
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  • Figure 8: venous vascular territories (illustration)
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  • Figure 8: venous vascular territories of the medial cerebral cortex (illustration)
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  • Figure 9: decussation of fibers in the brainstem (Gray's illustration)
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  • Figure 10: brainstem tracts (Gray's illustrations)
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  • Figure 11: brainstem tracts (Gray's illustrations)
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  • Figure 12: brainstem tracts (Gray's illustrations)
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  • Figure 13: brainstem cross-sectional anatomy (diagrams)
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  • Figure 14: brainstem arterial territories
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