Pyramidal symptoms, when they appear, indicate damage to the cortical-spinal (pyramidal) tracts, conducting excitations necessary for the formation of arbitrary movements. What is the pyramid system for? What are the symptoms of its damage?
Pyramidal symptomsis a characteristic group of symptoms that occur when the upper motor neuron, i.e. the motor centers located in the frontal lobes of the central nervous system, is damaged. The pyramid system is responsible for making conscious, purposeful and deliberate movements. It is the descending motor pathway that begins in the large pyramidal neurons of the motor cortex of the brain or the brainstem and goes to the α-motor neurons of the anterior horns of the spinal cord. The axons beginning in these neurons travel through the anterior roots of the spinal nerve, its trunk, and then its branches to the muscle fibers, controlling posture, muscle tone, reflex responses, and above all, free body movements.
Pyramid symptoms: list
The pyramid symptoms include:
- muscle weakness, paresis or paralysis
- occurrence of pathological symptoms (Babinski's symptom, Rossolimo's symptom)
- intensification of spastic (pyramidal) muscle tension in the case of damage to the reticular system or weakening / abolition of muscle tension in the case of "pure" damage to the motor neuron (in practice, damage to the neuronal bodies themselves)
- lack or weakening of skin reflexes (abdominal, plantar)
- excessive deep reflexes
- presence of exorbitant tendon reflexes
- no muscle wasting is observed - if any, they are secondary to inactivity
Symptoms of paralysis with the above features is called spastic paresis. However, as in other neurological syndromes, the upper motor neuron syndrome is not always fully expressed. It should also be remembered that in the first phase, after damage to the upper motor neuron, flaccid paresis appears with weakening or abolition of tendon reflexes, referred to as spinal shock syndrome. The reasons for this phenomenon remain unclear.
Pyramid symptoms: damage location
The ascertainment of pyramidal symptoms in the examination requires establishing which level of the centerthe nervous system was damaged. Depending on the location of the damage to the pyramidal pathways, the damage to the central motor neuron can take the following forms:
- damage to the cortex of the brain- paresis or paralysis limited to a small structure, e.g. of a hand, foot or one limb (so-called monoplegia) on the opposite side from the lesion, usually accompanied by symptoms irritations of the cerebral cortex, such as seizures or aphasia,
- damage to the inner capsule- paralysis or hemiparesis on the side opposite to the lesion, with frequent hemiparesis,
- brainstem damage- hemiplegia on the side opposite to the site of damage (i.e. left hemiplegia indicates right-side damage to the stem), usually accompanied by palsy of the cranial nerves on the side of the lesion, which gives the symptom of the so-called alternating hemiplegia,
- spinal cord injurieswhere the symptoms of spastic paralysis are accompanied by disorders of the extrapyramidal nerve pathways, such as sensory pathways, and the paralysis itself is usually bilateral, causing symptoms of tetraplegia or paraplegia .