Symptoms of the defeat of the medulla oblongata

The oblong brain is an extension of the spinal cord and has similar structural features - it consists of conducting paths and nuclei. At the front, it borders the bridge of the brain, and in the rear without a clear boundary passes into the spinal cord (conditionally the lower edge of the medulla oblongata is considered to be the intersection of the pyramids or the upper boundary of the first cervical spinal roots).

On the ventral surface of the medulla oblongata there is anterior median slit, on its sides - pyramids. The outer pyramids are the lower olives, separated from them by a lateral anterior groove. On the dorsal surface of the medulla oblong below the rhomboid fossa, the posterior cords (thin and wedge-shaped fascicles) are distinguished, separated by an unpaired posterior medial groove and paired posterolateral grooves. The dorsal surface of the anterior region of the medulla oblongata forms the bottom of the ventricle (the posterior corner of the rhomboid fossa). Outside of all the edges on the lateral surface of the medulla oblongata, the lower legs of the cerebellum are traced.

In the transverse section of the medulla oblongata, the pyramidal tract extends in its ventral region, fibers of the medial loop intersect in the central part (impulses of deep sensitivity from the nuclei of the thin and wedge-shaped bundles to the thalamus). Ventral-lateral divisions of the medulla oblongata occupy the lower olives. The ascending conductors, forming the lower legs of the cerebellum, as well as the dorsal-thalamic fascicle, are more dorsal than them. In the dorsal region of the medulla oblongata nuclei of the posterior group of cranial nerves (XX pair) are located, as well as a layer of the reticular formation.

In the bottom V of the ventricle (rhomboid fossa), the nuclei of many cranial nerves are located. At the level of the lower (posterior) corner are the nuclei of the sublingual (medially) and vagus nerves (laterally). At the level of the outer corner of the rhomboid fossa parallel to the median sulcus lies the sensitive nucleus of the trigeminal nerve, lateral it is the vestibular and auditory nuclei, and the medial core is the nucleus of a single path (the taste kernel of the glossopharyngeal and vagus nerves). Parametrically anterior to the nucleus of the sublingual nerve, the motor nucleus of the glossopharyngeal and vagus nerves and salivary nuclei are located.

Syndromes of the medulla oblongata: symptoms of impaired function of the nuclei and roots of the X, X, X and X pairs of cranial nerves, lower olive, spinal-thalamic tract, thin and wedge-shaped bundles, pyramidal and descending extrapyramidal systems, descending sympathetic fibers to the cilioplexal center , posterior and anterior spinal cord pathways.

The main alternating syndromes are the following.

The Avellis syndrome: peripheral paralysis of half of the tongue, soft palate and vocal cords (X, X, X pairs of cranial nerves) on the side of the focus and hemiplegia - on the opposite; develops in the hearth in one half of the medulla oblongata.

Jackson syndrome: peripheral paralysis of tongue tongue tongue on the side of the focus and the central paralysis of the opposite limbs occurs when one pyramid of the medulla oblongata and the spine X of a pair of cranial nerves are affected.

The Wallenberg-Zakharchenko syndrome: the defeat of the vagus nerve on the side of the focus (unilateral paralysis of the soft palate, the vocal cords, swallowing disorder, on the same side Bernard-Horner's symptom, cerebellar type ataxia, face anesthesia, dissociated anesthesia on the opposite side (alternating hemianesthesia) when blood circulation is disturbed in the vertebral or posterior lower posterior cerebellar artery, the ischemic focus is located in the dorsolateral region of the medulla oblongata.

Syndrome Schmidt: on the side of the focus paresis of the vocal cords, soft palate, trapezius and sternocleidomastoid muscle; on the opposite - spastic hemiparesis, ie, the nuclei and fibers of IX, X, XI, XII pairs of cranial nerves and pyramidal system are affected.

Tapia syndrome: on the side of the focus paralysis of the trapezius, sternocleidomastoid muscle (accessory nerve) and half of the tongue (sublingual nerve), contralateral spasmodic hemiparesis.

The Vopleshtein syndrome; on the side of the focus paresis of the vocal cords due to the defeat of nucl. Ambiguus, contralateral - hemianesthesia of surface sensitivity (spinal-thalamic tract).

Babinsky-Najotta syndrome: on the side of the focus - cerebellar symptoms (ataxia, nystagmus, asynergia), Claude Bernard-Horner's syndrome, hyperthermia; contralateral spasmodic hemiparesis, dissociated hemianesthesia (pain and temperature sensitivity fall out); the syndrome is caused by the defeat of the posterolateral region of the medulla oblongata and the bridge of the brain.

Glyk's syndrome: characterized by a combined lesion, V, V, X nerves and pyramidal system; on the side of the focus - vision loss (or amaurosis), pain in the supraorbital region, paresis of facial muscles, difficulty swallowing; contralateral spasmodic hemiparesis.

With bilateral damage to the nuclei and rootlets of X, X, and X pairs of cranial nerves, bulbar paralysis develops. It is characterized by impaired swallowing (choking, ingestion of liquid food in the nose), changes in the sonority of the voice (hoarseness, aphonia), the appearance of nasal hue of speech (nasolalia), dysarthria. Atrophy and fascicular twitching of the muscles of the tongue are observed. The pharyngeal reflex disappears. This syndrome most often occurs with vascular and some degenerative diseases (amyotrophic lateral sclerosis, syringobulbia).

Pseudobulbar paralysis is the central paralysis of muscles innervated by X, X, X with cranial nerve pairs. It develops with bilateral damage to the cortical and nuclear pathways. Foci are located at different levels above the medulla oblongata, including the brain stem. Clinical manifestations are similar to those in tabloid paralysis (violation of swallowing, nasal hue of the voice, dysarthria). With pseudobulbar paralysis reflexes of oral automatism appear (proboscis, palmar-chin, lingual-labial, etc.), violent laughter and crying. Symptoms of affection of the peripheral neuron (atrophy, fascicular twitching, etc.) are absent. The syndrome is most often associated with vascular lesions of the brain.

Thus, pathological foci in the brain stem can involve the pyramidal system and the motor nuclei of the cranial nerves. In addition, this may damage the conductors of sensitivity, as well as the nuclei and roots of sensitive cranial nerves. At the same time, neural formations are located in the brain stem, which exert an activating and inhibitory effect on the vast zones of the brain and spinal cord. This refers to the function of the reticular formation of the brain stem. It has extensive connections with the lower and upper divisions of the brain. Numerous collaterals from specific sensitive pathways approach the reticular formation. Pulses pass through it, which tone the cortex and subcortical structures and ensure their activity and the waking state of the brain. The inhibition of the ascending activating influences leads to a decrease in the tone of the cortex and the onset of drowsiness or real sleep. On the descending paths, the network-like formation sends pulses that regulate muscle tone (amplifies or reduces).

As part of the reticular formation, there are separate areas that have a certain specialization of functions (respiratory, vasomotor and other centers). The reticular formation participates in the maintenance of a number of vital reflex acts (breathing, cardiovascular activity, metabolism, etc.). When the brain stem, especially the medulla oblongata, is affected, in addition to those described above, severe symptoms such as respiratory and cardiovascular disorders also occur.

When the function of the reticular formation is disturbed, sleep and wakefulness disorders develop.

Narcolepsy syndrome: attacks of the patient's uncontrollable aspiration to fall asleep in a completely unsuitable environment (during a conversation, eating, walking, etc.); paroxysms of narcolepsy are often combined with paroxysmal loss of muscle tone (cataplexy), which occurs during emotions, which leads to immobility of the patient within a few seconds or minutes; Sometimes it is impossible to actively move for a short period of time immediately after awakening from sleep (cataplexy of awakening, or "night paralysis").

There is another type of sleep disorder - the syndrome of "periodic hibernation": sleep attacks lasting from 10 to 20 hours to several days, Klein-Levin syndrome: seizures are accompanied by bulimia. Thus, the reticular formation can participate in the formation of syndromes that arise when the focus is localized not only in the trunk, but also in other parts of the brain. This emphasizes the existence of close functional connections according to the principle of neuronal circles, including cortical, subcortical and stem structures.

In pathological foci outside the brainstem (extratrunally), several closely located nerves may suffer, and characteristic syndromes develop. Among them, it is important to note the syndrome of the bridge-cerebellar angle - the defeat of the auditory, facial and trigeminal nerves. It is characteristic for neuroma V of a pair of cranial nerves and basal arachnoiditis.

Syndrome of internal auditory meatus (Lyanitsa syndrome): damage to the auditory nerve, ear noise, hearing loss by sound-type type), facial nerve (peripheral paralysis of mimic muscles, dry eyes, decreased taste on the front third of the tongue) on the side of the hearth; occurs also in neurinoma V of a pair of cranial nerves.

The Gradenigo-Lannoy syndrome (a syndrome of the apex of the pyramid of the temporal bone): pain in the trigeminal nerve innervation zone (irritation of the trigeminal node), paralysis of the external rectus of the eye muscle on the side of the focus; appears with inflammation of the middle ear and with a tumor localized in the middle cranial fossa.

In the tumor nature of extratruncal lesions in the subsequent stages of the development of the disease due to compression of the brain stem, conductor disorders also join.

[1], [2], [3], [4]