THE SYMPATHETIC SYSTEM 105 



These contractures are painful, involuntary and resist 

 all attempts to overcome them. They occur after a 

 simple movement, a change of position or without any 

 apparent cause. 



They can be brought out by Trousseau's sign: a com- 

 pression of the arm at the level of the median nerve or 

 above the clavicle at the height of the brachial plexus, will 

 cause a tingling sensation followed by a contracture. 



In some cases, these contractures become generalized 

 and invade the upper limbs, the trunk, the legs, and the 

 face. The hands become flexed at an acute angle to the 

 WTists, the forearms on the arms; the latter are pressed 

 tightly against the body. The legs are usually in exten- 

 sion. In the face the contractures are manifested by 

 trismus, spasm of the eyelids and a sardonic smile. The 

 lips are pushed forwards and simulate the mouth of a fish. 

 The contracture may involve the muscles of the pharynx 

 (dysphagia) and the larynx (spasm of the glottis), the 

 vesicle sphincter (retention of urine), etc. Its generali- 

 zation resembles the clinical picture of tetanus. 



In certain abnormal cases the contracture stays localized 

 to a group of muscles (muscles of one of the hands, for 

 instance) or to one muscle (contracture of the thumb, 

 spasm of the eyelids). The most important of these iso- 

 lated contractures is that involving the muscles of the 

 larynx. As has been shown by Bouchut, Laryngospasm is 

 always a symptom of tetany. The spasm is then called 

 phreno glottic. Laryngospasm is often seen in the 

 tetany of infants. 



B. HYPEREXCITABILITY OF THE NERVES AND MUS- 

 CLES. This can be brought out by means of mechani- 

 cal or electrical stimulations. 



(a) The percussion of the facial nerve, done on the 

 middle of a line between the external auditory canal and 



