[Two symptoms of elective paresis of individual hand muscles].

The author describes 2 symptoms of elective lesions of the hand muscles: one of the central genesis, the other--peripheral, vegetative. The first symptom is characterized by a weakening of volar and dorsal interossal muscles of the hand in an increased electrical activity, which is beyond the weakened muscles. It is due to a lesion of filogenetically new cortico-spinal path, adjacent to the pyramidal and participating in the innervation of the muscles of the distal parts of extremities. The second symptom is "the symptom of the fifth finger", which is characterized by a selective weakening and decreased electrogenesis of the muscles in the fifth finger--abductor, adductor and the flexor brevis. Due to this it is likely caused by the activation of beta2-adrenoreceptors in the neuromuscular synapse, evoked by the irritation of cervical sympathical nodes and seen in degenerative changes of the cervical intravertebral discs, isolated cervical sympathalgia and toxico-infectious vegetative-vascular processes, especially hypothalamic.