【Recommended】Basal ganglia-internal capsule-thalamic anatomy

Recommended: basal ganglia-internal capsule-thalamic anatomy

Basal ganglia anatomy

The basal ganglia are gray matter clumps buried deep in the cerebral hemispheres on both sides and are the main structures
that make up the extrapyramidal system.
It mainly includes caudate nucleus, legume nucleus (putamen and globus pallidus), as well as screen nucleus and amygdala
.

The putamen and caudate nuclei are called neostriatum; The globus pallidum is called the old striatum
.

They are closely related
to the red nucleus of the midbrain, the substantia nigra, the inferior olive nucleus of the medulla oblongata, and the dentate nucleus of the cerebellum.

From a clinical point of view, it is collectively referred to as extravertebral lineage
.

Its descending fibers mainly include the covered spinal tract, the red nucleus spinal tract, the reticulospinal tract and the olive spinal tract
.

Extravertebral lesions are difficult to locate and have no practical significance
.
Generally speaking:

1.
Pallidus ball and substantia nigra damage

The main ones are tremor paralysis, the more serious the globus pallidus, the more pronounced
the increase in muscle tone.

2.
Shell nucleus and caudate nucleus damage

Mainly shows dance-like movements
.
Athetoid and torsional spasm, increased or variable
muscle tone.

3.
Dentate nucleus and lower olive nucleus damage

Myoclonus
occurs.

Tripolar syndrome and its causes

Hemisensory loss: radiation damage to
the central center of the thalamus.

It is a fibrous bundle from the posterior ventral nucleus of the thalamus to the retrocentral gyrus, transmitting sensations in the skin, muscles, and joints, and if this area is damaged, there is a contralateral somatosensory impairment
.

Contralateral hemiplegia: corticospinal tract and cortical nuclear tract injury
.

The corticospinal tract is a fibrous tract that descends from the anterior central gyrus to the motor nuclei of the somatic bodies of the brainstem, and the corticospinal tract is a fibrous tract that develops fibers from the middle and upper central gyrus and the anterior paracentral lobule to the motor nucleus of the anterior horn of the spinal cord, descending to the conical cross of the medulla oblongata, most of which cross to the opposite side
.
So contralateral hemiplegia
occurs.

Contralateral hemianopia: impaired
visual radiation.

One visual area receives impulses from the ipsilateral hemiretina of both eyes, and damage to one visual area can cause hemianopia of the opposite visual field of both eyes is called isotropic hemianopia
.

Anatomy of the thalamus

1.
The prenucleus group is related to
visceral activity.

2.
The medial nucleus group is the integrated center of the body and visceral sensation, and is also related to
memory function and emotional regulation.

3.
Lateral nuclear group: Among them, the ventral nuclear group includes:

Thalamic lesions can produce thalamic syndrome

Mainly contralateral sensory loss and/or irritation, contralateral involuntary movement
.

and may have emotional and memory impairments
.

Thalamic damage mainly produces the following symptoms:

1.
The lateral thalamic nucleus group, especially the posterior ventrolateral nucleus and the posterior ventromedial nucleus, are damaged to produce contralateral hemisensory impairment, which has the following characteristics:

2.
Fibrous contact from the thalamus to the subcortical (extrapyramidal system) nerve nuclei is involved, resulting in facial expression dissociative dyskinesia
.
That is, when the patient cries and laughs, the lesion loses its expression to the side, but when the patient makes random movements, the facial muscles are not paralyzed
.

3.
The contact fibers between the lateral thalamic nucleus group and the red nucleus, cerebellum, and globus pallidus are damaged, resulting in involuntary movements of the contralateral hemisphere, which may occur chore-like movements or athetosis-like movements
.

4.
Impaired communication between the anterior thalamic nucleus and the hypothalamus and limbic system produces emotional disorders, manifested as emotional instability and forced crying and laughter
.