Stroke And Bell's palsy Flashcards
What is Bell’s Palsy?
Inflammation of the facial nerve as it exits the styloid foramen which causes the weakness of the facial nerves- it is primarily an injury of the lower motor neuron.
How does Bell’s Palsy present?
LMN lesion which causes Smooth ipsilateral upper and lower facial muscles, but the upper facial muscles are relatively preserved because they receive innnervation from the contralateral side.
There is drooping, drooling, smooth forehead and eyelid remains open so eye-drops and taping the eyelid shut is important at night.
What is the course of the facial nerve?
Upper motor neurons arising from the cortex and travelling to the pons decassates to the contralateral cerebral hemisphere and synapse with lower motor neurons in the pons.
Lower motor neurons of the facial nerve nucleus arising from the pons to exit the stylomastoid foramen and innervate the ipsilateral facial muscles.
Why are the facial muscles affected differently in the face?
Muscles of the lower face only receive innervation from the contra lateral cerebral cortex or ipsilateral facial nerve nucleus.
The only exception is the muscles of the forehead which receive motor supply from both the ipsilateral and contralateral lower motor neurons/hemispheres.
What is a stroke?
Lesion to the upper motor neuron which affects the contralateral facial and arm muscles , with relative sparing of the forehead due to ipsilateral motor cortex innervation.
What is the presentation of stroke?
Wrinkling of the forehead but complete contralateral lower face paralysis with drooping.
How does a trochlear nerve palsy present?
Affects the superior oblique for the depression of the eye in the medial aspect. Results in diploma when looking vertically.
Cause of subdural haemorrhage
Venous Bleeding of bridging veins between cortex and venous sinuses
Cause of intracerebral haemorrhage
Anterior/ middle cerebral artery damage
Cause of epidural haemorrhage
Anterior cerebral haemorrhage
