1. Alastair Stephens Karina Bennett
Brainstem
Alastair Stephens
Karina Bennett

2. 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

3. 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

4. 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

5. 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.

6. 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?

7. 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

8. 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

9. 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?

10. 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