The inner capsule of the brain is a white substance, presented in the form of a curved strip and located in the gap between the ganglia of the base of the subcortex. It consists of equipped "conductors" - projection fibers that provide a connection between the brain itself and other further located areas of the central nervous system.
Anatomical structure of capsula interna
The anterior (located between the caudate nucleus of the reticular formation - nucleus caudatus and amygdala - nucleus lenticularis) and the posterior nucleus (between the visual zone of the thalamus - thalamus opticus and the same amygdala - nucleus lenticularis) are distinguished. In addition to genu capsulae internae (front and back thigh), there is also a knee. It is located in the area of the inflection of the capsule.
The inner capsule of the brain is important.
The main pathways passing through the white matter of the brain
Tractus cortico-bulbaris provides the relationship between the cortical substance and the nuclei of the cranial nerves.
Tractus cortico-spinalis consists of central motor fibers, like the previous tract, and reaches the anterior horns of the spinal cord, passing through the anterior two-thirds of the hind femur so that the fibers for the upper limb are located anteriorly, and for the lower limb anteriorly. What is axon and dendrite? About it further.
Tractus thalamo-corticalis pass from the area of the optic tubercle to the cortex, located behind the previous path.
Directly the visual paths, starting from the primary centers of view of the corpus geniculatum laterale, ending with the occipital lobe (radiatio optica) - the Gracioli bundle.
Starting from the subcortical region and ending with the primary auditory center in the temporal lobe (corpus geniculatum mediale), the auditory tract is located.
Tractus fronto-pontinus, that is, the frontal pathway, reaches the bridge and cerebellum, while occupying the front thigh of the inner capsule.
The occipital-temporal tract (tractus occipito-temporo-pontinus) passes, respectively, between the cortex and the temporal-occipital region.
Tractus cortico-thalamici lies in the front and back thighs and provides a link between the visual tubercle and the cortex.
Since nerve fibers cross in the direction of their location, the diagnostic criterion will be damage to the opposite side of the limb, if it affects sensitive fibers, then at the level of their overlap in the spinal cord and medulla oblongata, and motor nerves (pyramidal pathways) at their border.
With complete damage to the inner capsule of the brain, they speak of the "three hemi syndrome":
• Hemiplegia (lack of independently performed movements).
• Hemianesthesia (complete loss of sensation) on the opposite side of the trunk.
• Hemianopsia (blindness of both eyes affecting half of the field of view).
Axon and dendrite are the components of a neuron. Axon is a long process, the length of which can be several meters. They perform a function - transmit information from the body of a neuron to other CNS cells.
The dendrites of a neuron are called multiple nerve fibers, which are a collector of information, that is, transmit it to the body of a nerve cell.
Hemiplegia
As a rule, the same percentage of involvement of the upper and lower limbs in this process takes place. Often paresis develops simultaneously of the tongue and muscles of the lower part of the face according to the central type.
The anatomy of the inner brain capsule is of interest to many.
Hemianesthesia
Half nature and often affects the distal (lower located) parts of the limbs. If the area above the visual tubercle is affected, such types of sensitivity as, for example, pain and temperature, muscular-articular and other types, can occur. Gross lesions are combined with a sense of irradiation, fuzzy location and the presence of aftereffect, that is, there is hyperpathy.
Hemianopsia
It is characterized by damage to the fibers that make up the Graciola beam with the observed aftereffect on the opposite side.
Most often, severe and complicated lesions on the part of the auditory apparatus are not observed, which is primarily due to bilateral localization of the pathways, therefore the sound received in the ear canal, changing in momentum, reaches both the right and left hemispheres.
Depending on which part was affected by the traumatic effect, and on which section of the track is located there, we can predict the further development of the situation. So when touching the area of the knee of the inner capsule of the brain and the anterior portion of the hind femur, hemiplegia will be expressed in the absence of pathological changes from the motor or other other sensitivity.
If the opposite part (the back of the thigh) is affected, the effect will be the opposite.
A white matter group (centrum semiovale) located between the ganglia and the cerebral cortex is also isolated. This section contains projection and associative fibers. The first connects the cortical substance with the underlying departments, located almost perpendicularly. They are represented by corticosteroids and corticosteroids.
What else is interesting in the structure of the inner capsule of the brain?
Association beams interconnect different departments within the same hemisphere. It can be both short (V-shaped), connecting adjacent convolutions, and long (fasciculus longitudinalis superior et fasciculus longitudinalis inferior, for example). Commissural fibers, which, unlike other types of fibers, interact outside the hemispheres, facilitate their interaction.
Corpus callosum
The corpus callosum is the most important and powerful bundle of all commissural fibers. This formation connects the same share: the parietal of the right hemisphere with the same share only of the left hemisphere and so on. Corpus callosum is also involved in the formation of the olfactory tract, passing through the anterior and posterior white commissures.
Foci of white matter localized on both sides (such as, for example, centrum semiovale, capsula interna), predispose to the appearance of pseudobulbar disorders of both speech and swallowing, mainly due to a pathological change from two tractus cortico-bulbaris. In addition, bilateral pyramidal symptoms join due to violations in the tractus cortico-spinales on both sides. Often, phenomena of violent crying or laughter, other types of pseudobulbar disorder and hypomimia are added to everything.