Alastair Stephens Karina Bennett Brainstem Alastair Stephens Karina Bennett

Label the anterior brainstem. Optic tract CN III Midbrain Interpeduncular fossa Pons CN V Cerebellar peduncle CN VI, VII and VIII Medulla Pyramids Descending corticospinal tracts

Label the posterior brainstem. Thalamus Pineal gland Midbrain Superior colliculus linked to visual pathway Inferior colliculus linked to auditory pathway Pons CN IV Emerges from posterior brainstem & decussates Cerebellar peduncle Medulla Dorsal columns Fasciculus cuneatus and gracilis

Roughly describe where the cranial nerves exit the brainstem. CN I (links to piriform cortex) CN II (links to lateral geniculate body) 1 2 CN III & IV: Midbrain CN V: Pons CN VI –VIII: Pontomedullary junction CN IX & X: Lateral medulla CN XI: C1-C5 spinal cord CN XII: Ventral medulla 3 Mid 4 5 Pons 6 7 8 9 10 12 Med 11

What will an UMN lesion to this cranial nerve result in? Nearly all cranial nerve motor nuclei receive bilateral supply from the motor cortex, except which cranial nerve? CN VII controlling lower face What will an UMN lesion to this cranial nerve result in? The forehead part of the nucleus receives bilateral UMN innervation The lower face part receives only contralateral UMN innervation An UMN lesion will result in paralysis of the contralateral lower face but forehead sparing Also the eye ones 3, 4 and 6 don’t receive bilateral supply from the motor cortex. SO they can wrinkle their forehead butt he lower face is paralysed.

What is the difference between bulbar palsy and pseudo-bulbar palsy? Bulbar palsy: a lower motor neuron lesion affecting CN VII-XII Flaccid paralysis of the pharynx and larynx Pseudo-bulbar palsy: a bilateral upper motor neuron disorder Spastic paralysis of the pharynx and larynx = airway occlusion emergency Pseudo bulbar can first present as a LMN problem. Why?

Label the blood supply to the brainstem. Anterior communicating Anterior Cerebral artery Internal carotid artery Middle Cerebral artery Posterior communicating Superior Cerebellar artery Posterior cerebral artery Basilar artery Pontine arteries Anterior inferior cerebellar artery (AICA) Anterior spinal artery Posterior inferior cerebellar artery (PICA) Vertebral artery

How are brainstem nuclei ordered into areas according to their type? What are the 3 visceral motor and visceral sensory nuclei called? Somatic Sensory Somatic motor Visceral Motor & Sensory Nucleus Ambiguus Motor supply to branchiomotor muscles (pharynx, palate and larynx). Nucleus Solitarius Special sensory information via visceral afferents: taste, visceral sensation (respiratory tract and GIT) and carotid body/sinus sensations (baroreceptors and chemoreceptors). Salivatory nuclei SM SS VM & VS

Steve, an 79 year old man, suffered a brainstem stroke Steve, an 79 year old man, suffered a brainstem stroke. Examination revealed an infarction in the region shown by the grey oval in the image and tissue deep to this point. Which cranial nerve is likely to damaged in this location? Explain the most likely cranial nerve examination findings associated with a lesion in this areas. What artery is likely to be blocked to cause the lesion shown. What other structures may also be damaged?

Which cranial nerve is likely to damaged in this location? CN V 2. Explain the most likely cranial nerve examination findings associated with a lesion in this areas. Loss of sensation in all 3 divisions of the left side of the face No left corneal reflex (sensory component) Paralysed left muscles of mastication 3. What artery is likely to be blocked to cause the lesion shown. What other structures may also be damaged? Pontine arteries Left cerebellar peduncle