Differences of intra axial and extra-axial lesions of the brain stem
How do the presentations of intra axial and extra-axial lesions of the brain stem differ?
A lesion that directly affects the tissues of the brain stem is called intra-axial or intramedullary.
It usually presents with simultaneous cranial nerve and long-tract symptoms and signs.
A lesion outside the brain stem is called extra-axial .
It affects the brain stem by initially compressing and interfering with the functions of individual cranial nerves.
Later, as it enlarges, neighboring structures within the brain stem may be affected, causing additional long-tract signs.
