Symptoms of affecting the midbrain
Last reviewed: 23.04.2024
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The roof of the midbrain is the plate of the roof, the base is the legs of the brain, in the middle part the nuclei of the midbrain are located.
The dorsal part (roof) of the midbrain is located posteriorly from the aqueduct of the brain and is represented by a plate of the roof. It has two upper and lower mounds. The lower hills are constructed more simply and consist of medium-sized neurons. These mounds provide hearing and complex reflexes in response to auditory stimuli.
The upper hills are more organized. They carry out automatic reactions associated with the visual function, that is, they participate in the realization of unconditioned reflexes in response to visual stimuli (closing eyes, pulling off the head, etc.) - start-reflexes. In addition, they coordinate the movements of the trunk, mimic reactions, movements of the eyes, the head, and others in response to visual stimuli. These reflex reactions are provided by the spinal-spinal tract, which originates in the upper hills.
Below the plate of the roof is the water pipe of the brain, which is surrounded by a layer of the reticular formation.
The legs of the brain are dense strands of white matter (descending paths), conditionally they can be divided into three parts: the outer, middle and inner. Outside, there pass the fibers of the occipital-temporal-bridge and frontal-bridge pathways, which are then sent to the cerebellum. The fibers of the pyramidal system (the cortical-nuclear and cortico-spinal cord) pass through the middle part of the brain stem. Fibers innervating the muscles of the face and tongue are located medially, the muscles of the lower limbs are lateral, and the muscles of the upper limbs are in the middle. On the border of the legs of the bridge with the tire is the core of black matter, lying in the form of a plate on the conducting paths. Between the roof of the midbrain and the black matter are the red nucleus, the nuclei of the oculomotor and block nerves, the medial longitudinal fasciculus and the medial loop. Two bundles of fibers of the medial longitudinal bundle are located paramedically at the bottom of the aqueduct of the brain. At the same level, more externally, lie the nucleus of the oculomotor (at the level of the upper hills) and the block nerves (at the level of the lower hills). The red nucleus is between these nuclei and the medial longitudinal bundle, on the one hand, and with the black substance on the other. In the lateral part of the midbrain pass afferent fibers - the medial loop (consisting of the bulboltalamic tract fibers). It carries out impulses of deep sensitivity from the thin and wedge-shaped nuclei of the medulla oblongata and the spinal-thalamic tract, the conductors of surface sensitivity. In the anterior midbrain, at the level of the upper hills, the nuclei of the medial longitudinal fascicle are localized.
When the nuclei or roots of the oculomotor nerve are affected, external, internal total ophthalmoplegia develops; (spontaneous vertical nystagmus - bobing syndrome), discoordination of eyeball movements, ophthalmoplegia, horizontal nystagmus, Notnagel syndrome (imbalance, hearing, paralysis of oculomotor muscles, choreic hyperkinesia), paresis and paralysis of the limbs, cerebellar disorders, decerebral rigidity (associated with the defeat of the midbrain centers regulating the muscle tone below the red core).
Porto's syndrome: vertical paresis of the eye, violation of convergence of eyeballs, partial bilateral ptosis of the eyelids; horizontal movements of the eyeballs are not limited; the syndrome is observed when the upper mounds of the roof of the midbrain and in the epiphysis tumor are affected.
Syndrome of the red nucleus: intentional hemitremor, hemi-giperkinesis; Claud syndrome (lower red core syndrome): oculomotor nerve lesion (ptosis, divergent strabismus, mydriasis) on the side of the focus; Intensive hemithremor, hemiataxia and muscle hypotension - on the opposite side.
Fua syndrome (upper syndrome of the red nucleus): intentional hemithremor, hemygiperkinesis.
Syndrome of black matter: plastic muscle hypertension, akinetic-rigid syndrome on the opposite side to the side.
Tegmental syndrome: on the side of the focus - ataxia, Claude Bernard-Horner's syndrome, tremor, myoclonus on the opposite side to the side - hemihypesthesia, disorders of the quadruple reflexes (rapid orientation movements in response to unexpected visual and auditory stimuli - start reflexes).
Weber's syndrome: peripheral paralysis of the oculomotor nerve on the side of the focus and hemiparesis (hemiplegia) - on the opposite; the focus is located at the base of the brain stem and breaks the pyramidal bundle and the fibers of the oculomotor nerve.
Benedict's syndrome: paralysis of the oculomotor nerve on the side of the focus (ptosis, divergent strabismus, mydriasis), intentional trembling and athetoid movements in the extremities on the opposite side to the side; the focus damages the fibers of the oculomotor nerve, the red nucleus and the corresponding cerebellar conductors of the dentate-red-blooded path.
With the defeat of one half of the bridge of the brain, the following alternating syndromes develop.
Mikkra-Goebler-Jyubble syndrome: peripheral paralysis of facial muscles on the side of the focus and hemiplegia on the opposite side; the focus is located at the base of the lower part of the bridge of the brain, the nucleus n suffers. Facialis and a pyramidal bundle.
Fawill's syndrome: peripheral paralysis of facial muscles and the external rectus of the eye (convergent strabismus) on the side of the focus, hemiplegia - on the opposite; this syndrome occurs when the lower part of the base of the brain bridge is affected; the pyramidal fascicle, the nucleus of the facial and the axons of the cells of the nucleus of the nerve are affected.
Gasperipi Syndrome: peripheral paralysis of the abduction, facial nerve, hearing loss, hypesthesia in the trigeminal nerve zone on the side of the focus and conductive hemianesis on the opposite side; develops with a unilateral focus of the brain bridge cover.
Brissot-Sikar syndrome: spasm of facial muscles on the side of the lesion (hemispasm of the facial musculature from irritation of the nucleus of the facial nerve) and spastic hemiparesis on the opposite side of the lesion (lesions of the pyramidal system).
Raymond-Sestan syndrome: paralysis due to combined lesion of medial longitudinal fascicle and bridge center of gaze, middle leg of cerebellum, medial loop and pyramidal tract; observed paresis of the gaze toward the lesion, ataxia, choreoathetoid hyperkinesis - on the side of the focus; contralateral - spastic hemiparesis and hemianesthesia.
Grene's syndrome: on the side of the hearth - loss of surface sensitivity on the face by segmental type; contralateral - hemianesthesia of surface sensitivity on the trunk and extremities (damage to the nucleus V of a pair of cranial nerves and the spinal-thalamic tract).
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