What Is the Posterior Cerebellum?

Part of the brain. Located below the brain, in the posterior cranial fossa, the medulla oblongata and the back of the pons. It can be divided into the middle earthworm and the enlarged cerebellar hemispheres on both sides. The cerebellum surface has many shallow parallel grooves, with a leaf between the grooves. The gray matter on the surface is the cerebellar cortex, and the deep part is white matter, also called medulla. There are several pairs of nuclei in the white matter, called the central nucleus. The cerebellum is an important regulatory center of movement, with a large number of incoming and outgoing connections. Information about the movement of the cerebral cortex to the muscles and information from the muscles and joints during exercise can be transmitted to the cerebellum. The cerebellum often integrates these two kinds of nerve impulses, and adjusts and corrects the movement of the relevant muscles through the outgoing fibers to maintain coordination of voluntary movements. In addition, the cerebellum also plays an important role in maintaining body balance. It receives information from the vestibular organs and changes the tension of muscles in different parts of the body through outgoing connections, so that the body maintains a balanced posture during acceleration or rotation under the action of gravity. ^[1]

The cerebellum communicates with the brain,

In terms of afferent cerebellar afferents, they can generally be divided into two afferent systems: mossy fibers and climbing fibers. The mossy fiber afferent system includes: the impulses from the body's proprioceptors and external receptors.

The symptoms of cerebellar dysfunction are as follows:

l, ataxia: due to lack of cerebellar regulation, the patient stands unstable, shakes, gait is unstable, is a drunk gait: when walking, legs are far apart, swinging left and right, both upper limbs flexed forward and stretched like a fall . It is difficult to stand with your feet. Generally cannot stand with one foot. The abnormal handwriting is also a manifestation of ataxia of the arms and hands, with irregular handwriting and trembling strokes. Generally, writing is too large, while tremor and paralysis are mostly writing too small ^[3] .

Cerebellum

2. Outburst language: slow speech, crashing, monotonous, nasal sounds. There is "language of medulla oblongata", but the latter is more peculiar and clumsy, and objective examination often has vocal cords or palsy, while cerebellar speech is ataxia without paralysis. 3 Poor range or scale disorder.

4 Alternating movement disorder: The examinee repeatedly and quickly slaps the back of the other hand with the palm and back of one hand, or continuously and quickly pats on the bed or table. Patients with ataxia are awkward, slow, and irregular.

5. Synergies.

6. Counterattack sign.

7. Nystagmus.

8. Changes in muscle tone: Changes in muscle tone are difficult to estimate. It varies according to the location of the lesion and the period of the lesion, such as:

, typical cerebellar lesions (trauma, tumor) on one side of the ipsilateral half-body muscle tension decreased.

In patients with bilateral symmetrical cerebellar lesions, there is generally no significant change in muscle tone.

In some cases of cerebellar atrophy, a gradual increase in systemic muscle strength can be seen, which may appear similar to tremor paralysis.

1. Damage to pompom nodules can cause balance imbalance and standing instability, walking inability, striding too wide, staggering, drunk gait (trunk or axial ataxia), but ataxia when closing eyes will not Aggravated, which can be distinguished from ataxia caused by lesions in the posterior cord. Cerebellar ataxia has nothing to do with proprioceptive dysfunction, but is related to the incoordination of muscle group activity, so it is called synergy (Papillary Lobular Syndrome).

2. The damage section makes the hot and cold and rotation test response of the vestibular function disappear.

After the injury, ataxia of the trunk occurs, but it is rare that the injury is limited to the old cerebellum.

1. If the lesion is limited to the earthworm, symptoms are mostly ataxia of the trunk and speech disorders. Limbs are less abnormal and tension is normal. At present, there is a noticeable fact that in most cases of (chronic) diffuse cerebellar atrophy, the degree of degenerative lesions of the earthworm and hemisphere is equal, and clinically, it is mainly physical ataxia and language disorder, and the limb abnormality is relatively mild. This shows that the brain compensates the new cerebellum through a large number of projection connections.

2. On the positioning significance of the eruption language. It is necessary to cause lesions on both sides or in the middle of the earthworm, especially when the earthworm and the front of the hemisphere on both sides are affected. In some cases of limited cerebellar atrophy, only the worms and adjacent parts of the hemisphere have lesions, and clinically there is severe fulminant language. Delayed atrophy, mainly in the old cerebellum, can occur during alcoholism.