PMC4913175_01
Chiari malformation and spinal cord syrinx. Sagittal T1 (A), coronal T2 (B) and axial T2 (C) images show mild descent of the cerebellar tonsils, to just below the foramen magnum, though associated with an extensive spinal cord syrinx:from obex to lower thoracic cord (lower limit not shown).
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The vagus cranial nerve nuclei. With the decent of the brainstem in Chiari I malformation, these nuclei can become compressed. As labelled, the nucleus solitarius gives sensory fibres for taste, nucleus ambiguous gives branchiomotor supply to the larynx and the dorsal motor nucleus gives general efferent visceral fibres. Further along the course of the vagus nerve, the recurrent laryngeal nerve branches off to innervate the larynx, a commonly injured nerve causing vocal cord paralysis.
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