Medulla oblongata
Origin · CN IX CN X CN XI CN XII
IX, X and the cranial root of XI leave the lateral medulla behind the olive (postolivary sulcus) from the nucleus ambiguus, dorsal motor nucleus of the vagus and solitary nucleus; XII leaves as rootlets between the pyramid and the olive (preolivary sulcus) from the hypoglossal nucleus in the floor of the fourth ventricle.
Detail
- Gives rise to
- CN IX, X, XI cranial root (postolivary sulcus), CN XII (preolivary sulcus); spinal root of XI ascends from C1–C5 through the foramen magnum
- Nuclei
- Nucleus ambiguus (motor IX, X, XI cranial), dorsal motor nucleus of X (parasympathetic), solitary nucleus (taste and visceral sensation), hypoglossal nucleus, spinal trigeminal nucleus
When it goes wrong
Lateral medullary infarct from vertebral or posterior inferior cerebellar artery occlusion (Wallenberg syndrome)
Ipsilateral palatal and pharyngeal weakness with dysphagia and hoarseness (nucleus ambiguus), ipsilateral facial pain and temperature loss, Horner syndrome and limb ataxia; contralateral loss of pain and temperature in the trunk and limbs
Medial medullary infarct (anterior spinal or vertebral artery) involving the XII fascicle, pyramid and medial lemniscus
Ipsilateral tongue weakness deviating towards the lesion with contralateral hemiparesis and loss of proprioception and vibration
Motor neurone disease destroying the nucleus ambiguus and hypoglossal nucleus (bulbar palsy)
Nasal speech, dysphagia with aspiration, wasted fasciculating tongue and absent gag and jaw jerk
Practise this structure
1 question in the bank tagged Brainstem.