Anatomy
Bilateral ventral pons
Vascular
Basilar artery
Signs & Symptoms
| Side | Manifestation | Comments |
|---|---|---|
| Both | Weakness – upper and lower extremity | Quadriplegia: bilateral cortical spinal tracts |
| Both | Weakness – face – entire side | Bilateral corticobulbar tracts |
| Neither | Lateral gaze weakness | Bilateral fascicles of CN VI |
| Neither | Dysarthria | Bilateral corticobulbar tracts |
Notes
Bilateral ventral pons lesions (iscemic or hemorrhagic) may result in this deefferented state, with preserved consciousness and sensation, but paralysis of all movements except vertical gaze and eyelid opening.
- Quadriplegia due to bilateral corticospinal tract involvement
- Aphonia due to corticobulbar tract involvement to lower cranial nerve nuclei
- Occasionally, impairment of horizontal eye movements due to bilateral involvement of the fasciclesof cranial nerve
- Reticular formation is spared, so the patient is typically fully awake. The supranuclear ocular motor pathways lie dorsally, so that vertical eye movements and blinking are intact.