It crosses the superior cerebellar artery close to the cerebral peduncles
, passes the lateral edge of the clivus bone, and runs under the petroclinoidal ligament into the cavernous sinus between the double layer of dura and connective tissue at its lateral border, just below the oculomotor nerve and above the ophthalmic branch of the trigeminal (5th cranial) nerve.
On MRI brain (plain), there was a large(size) well defined cystic mass in right temporo-parieto-occipital region with mild vasogenic oedema and mass effects causing midline shift, compression of ipsilateral lateral and third ventricle and cerebral peduncle
This was first described by Kernohan et al (1) in 1929 after an autopsy study revealed a notched cerebral peduncle
from a contralateral herniation syndrome.
Kernohan and Woltman (1929) described this condition as an effect of compressive forces resulting in the midbrain being forced against the contralateral edge of the cerebral peduncle
CT scan and MRI shows typical signs in form of localised oedema in brainstem, cerebellar white matter, cerebral peduncles
, posterior limb of internal capsule, globus pallidus, perirolandic white matter.
Signal intensity was observed at the bilateral globus pallidus, hypothalamus, bilateral cerebral peduncles
, nucleus ruber, pons posterior, cerebellar dentate nuclei, bilateral periventricular deep white matter, and subthalamic nuclei and secondary ischaemia on T2-weighted images (Figures: 1a and 1b).