Correct combination
Case 109
【Discussion】
Medullary oblongata is approximately 3cm long and 2.5cm in wide at its largest point. When we examine neural routes or nucleus in cross-sections of lateral medullary oblongata (LMO), there can occur different travel course of neural routes or nucleus depending on the cross-section site. However, it is crucial to get acquainted with components of LMO in order to understand Wallenberg syndrome which indicates the ischemic damage of LMO.
The most lateral components of medullary oblongata are spinocerebellar tract or inferior cerebellar peduncle which implies the same route and functions ipsilateral motor coordination. Its damage causes ipsilateral ataxia and disorder of motor coordination. Both of our two cases experienced the ipsilateral weakness of extremities, indicating disorder of spinocerebellar tract or inferior cerebellar peduncle.
The lateral but a little bit inside components are spinothalamic tract and trigeminal nucleus and tract which innervate pain & temperature of contralateral hemi-body below face and pain & temperature of ipsilateral hemi-face, respectively. The ischemic damages of spinothalamic tract and trigeminal nucleus and tract cause numbness of contralateral hemi-body below face and numbness of ipsilateral hemi-face, respectively. Both of our two cases experienced numbness of contralateral hemi-body, indicating disorder of spinothalamic tract disorder.
The lateral but further inside and dorsal components are vagus nerve nucleus and central sympathetic nerve route which function auto-nerve coordination of respiratory and cardiac movement. When the disorder of vagus nerve occurs, it causes tachycardia and dyspnea, while the disorder of central sympathetic nerve causes Horner syndrome that is characterized miosis (constricted pupil), ptosis (week, droopy eyelid) and decreased seating. Our both cases did not experience the disorder of cardiac and respiratory disorders and Horner syndrome, indicating no damage of vagus nerve nucleus and central sympathetic nerve route.
The lateral but further inside and dorsal components are brain nerve nucleus: inferior vestibular (VIII) nucleus, ambiguous nucleus (IX, X, XI) and solitary nucleus (VII, IX, X), which functions equilibrium and balance, motor coordination of palate, pharynx and larynx, and taste, respiratory. When disorders of inferior vestibular nucleus, ambiguous nucleus and solitary nucleus occur, they cause dizziness and nystagmus, dysarthria and dysphonia, and no taste sense, respectively. Our case did not experience these symptoms, indicating no damage of inferior vestibular nucleus, ambiguous nucleus and solitary nucleus.
In the literature, of these symptoms of Wallenberg syndrome, gait disturbance, sensory symptoms, Horner’s sign and dizziness are the most common followed by dysphagia, hoarseness, vertigo and nystagmus.
Lateral medullary oblongata is supplied from a lateral medullary branch branched from posterior inferior cerebellar artery and/or perforating lateral medullary artery branched from vertebral artery. The thrombotic or embolic occlusion causes Wallenberg syndrome.
【Summary】
We present two cases of Wallenberg syndrome with infarction of lateral medullary oblongata, suffering from motor weakness of ipsilateral hemi-body and sensory numbness of contralateral hem-body, indicating disorders of spinocerebellar tract or inferior cerebellar peduncle, and disorder of spinothalamic tract. We should keep in mind that spinocerebellar tract or inferior cerebellar peduncle exists at the most lateral of LMO, spinothalamic tract and trigeminal nucleus and nerve at the lateral but a little bit inside, vagus nucleus and central sympathetic nerve at the lateral further inside and brain nerve nuclei of inferior vestibular nucleus (VIII), ambiguous nucleus (IX, X, XI) and solitary nucleus (VII, IX, X). Then, infarction of lateral medullary oblongata causes weakness of ipsilateral extremity, numbness of contralateral extremity and ipsilateral face, Horner’s sign, dysarthria, dysphonia and dysphagia. Of these symptoms, the most common symptoms are gait disturbance (ataxia), sensory symptoms and Horner’s sign and dizziness.
【References】
The content of this article is written by the book as below. Peter Duus. Neuroloigisch-topische Diagnostik: Anatomie Physiologie Klinik, second edition translated in Japanese by Hajime Handa and Junya Hanakita. Bunkodo, Tokyo
2018.6.20