31. TYPICAL FORMS OF PATHOLOGY OF THE NERVOUS SYSTEM. DISORDERS OF LOCOMOTION AND SENSATION

Based on the specific functions performed by the nervous system, its disorders can be divided into five groups:

1) disorders of locomotion;

2) disorders of sensation;

3) disorders of the autonomic functions control;

4) disorders of trophic function;

5) disorders of the brain cortical (higher nervous) functions.

In this textbook we discuss only disorders of locomotion and sensation. Typical forms of the nervous system dysfunctions are considered in fig. 40.

DISORDERS OF LOCOMOTION

Movements are conventionally divided into two types: voluntary and involuntary.

The voluntary movements are regulated by the pyramidal system consisting of two neurons - upper and lower.

The pyramidal system starts from the pyramidal cells of the frontal cortex. Axons of the upper motor neurons descend through the subcortical white matter and the brainstem to the spinal cord or to the motor nuclei of the cranial nerves. Lower motor neuron axons exit the brainstem in certain cranial nerves and the spinal cord in the ventral roots. The ventral roots fuse with the dorsal roots at the intervertebral foramen to form the spinal nerves for innervation of the limb muscles.

The involuntary movements are regulated by extrapyramidal system which includes subcortical nuclei and striapallidum pathways. The pathways of this system consist of 3 to 5 neurones and include corticorubral, corticoreticular, corticopontine, and other cortical-brainstem pathways. These pathways contribute to the lower motor neuron activity indirectly through the bulbospinal pathways.

Fig. 40

Types of locomotor dysfunction:

•  muscle weakness;

•  movement disorders;

•  ataxia, imbalance, other disturbances in the initiation or coordination of the movement.