MOTOR PARALYSIS. 335 



II. Motor Paralysis — Paresis. 



Motor paralysis, palsy, loss of power of motion, although it 

 may occur of itself, is more frequently associated with sensory 

 paralysis, the combined condition being earlier and more dis- 

 tinctly a loss of motion than sensation. It can scarcely of 

 itself be considered as a disease, rather as an indication of 

 such; while in the position of a symptom it occupies an 

 important position in all diseases of the nervous system. In 

 estimating its importance as an indication of tissue-change, 

 regard must be had to various points in its development, such 

 as its mode of attack, whether sudden or gradual, constantly 

 existing or subject to variations ; Avhether affecting a limited 

 number of muscles or very extensively distributed ; whether 

 influenced by volition or by causes from without. As our 

 patients affected with serious paralysis are rarely allowed to 

 live long, we seldom have the opportunity of watching changes 

 of trophic and other characters which are observed in man. 



According to the situations invaded, and some other con- 

 siderations, motor paralysis has received certain distinctive 

 names, as — 



1. General paralysis, in which, although the entire muscles 

 are not invaded, the disturbance is so extensive as to affect 

 both anterior and posterior members, and probably also cer- 

 tain muscles of the trunk. 2. TJnilateral paralysis, or hemi- 

 plegia. 3. Paralysis of a transverse character, or paraplegia. 

 4. Local paralysis, when the loss of motor-power is limited 

 to a circumscribed part of the body, a single muscle, or group 

 of muscles. 



1. General Paralysis is only seen in the horse as a temporary 

 condition in certain diseases of the cranial structures, in cere- 

 bral congestion, in effusion into the basal ganglia, and in 

 injuries and diseases of the anterior portion of the cord and 

 medulla. 



2. Hemiplegia, or one-side paralysis, is not often observed in 

 our patients ; it is usually the result of some interference with a 

 lateral section of the brain. On the side of the face correspond- 

 ing to the brain lesion, distinct change in the facial expres- 

 sion often occurs as the result of the loss of muscular power. 

 The angle of the mouth is relaxed, and the lip pendulous ; 



