TETANUS (derived from the Gr. teinein, to stretch), is one of the most formidable dis eases of the nervous system, and is characterized by an involuntary, persistent, intense, and painful contraction or cramp (see SPAsat) of more or less extensive groups of the vol untary muscles, nearly the whole of the body being sometimes affected. There is usually a certain degree of order in which the different sets of muscles are affected. The mus cles of the neck, jaws, and throat are almost always the first to give evidence of the pres ence of the disease. "The patient," says Dr. Watson, who has written a most graphic description of this terrible malady, "feels a difficulty and uneasiness in bending or turn ing his head, and supposes that he has got what is called a stiff neck. He finds also that he is unable to open his mouth with the customary facility. At length the jaws close; sometimes gradually, but with great firmness; sometimes (it is said) suddenly and with a snap. In four cases, perhaps, out of five, the disease begins in this way with trismus or so that this last is the vulgar name for the complaint. Along with this symptom, or very soon after it, the muscles concerned in swallowing become affected; and in a short time there comes on, what is often the most distressing part of the dis order, an acute pain at the lower part of the sternum, piercing through to the back. This pain depends, it can scarcely be doubted, upon cramp of the diaphragm, and is subject aggravation in paroxysms. The spasm extends to the muscles of the trunk-; to the large muscles of the extremities; the muscles of the face; and last of all, iu general to the muscles of the tongue, and of the hands and fingers, which often remain movable at the will of the patient, after all the other voluntary muscles of the body have become on the Principles and Practice of Physics, 4th ed., vol. i. p. 568. The muscles that are affected remain permanently contracted till either recovery or death ensues, and some of them, as, for example, the muscles of the abdomen, arc so rigid, as when struck by the fingers, to resemble a board, although a perfect remission of the spasm scarcely ever occurs, except sometimes during sleep. Exacerbations of the spasms, on the other hand, commonly occur every ten minutes or quarter of an hour, usually beginning by an increase of the pain at the sternum, and lasting for two or three minutes: and as the disease advances, these paroxys. s become more frequent. The powerful muscles of the back generally overcome the muscles in the front of the body, and when this excess of morbid power in the back is marked, the result is that the patient during the paroxysms rests solely on his head and heels, while his body is raised in an arched form. Occasionally the muscular contraction predominates in the opposite direction,
and brings the head and knees in contact; and still more rarely, the body is bent to one side.
During the exacerbations, the face of the patient often presents a positively frightful appearance. The tongue is apt to get bitten during the contractions, which are occasion ally so violent as to break the teeth, rupture powerful muscles, and at least in one case, to fracture the thigh-bone. Death usually results from a mixture of causes, but mainly from apnoea (breathlessness), due to the fixed condition of the respiratory muscles, asso ciated with asthenia (loss of power), and flagging of the heart's action.
There are two principal causes of this disease, viz. (1) exposure to cold and damp, and (2) bodily injuries. When tetanus arises from the first of these causes, it is termed idiopathic; and when from the second, traumatic. Idiopathic tetanus is so rare, at all events in this country, that we may pass on at once to the consideration of the traumatic variety. The disease is liable to follow any kind of injury, from a trifling cut or scratch to a compound fracture or the most severe operation, and is much more common in trop ical than in temperate climates. The following table, given by Mr. Poland in his article " Tetanus" in Holmes's System of Surgery, vol. i. p. 306, gives the relative proportions which the occurrence of tetanus bears to various classes of surgical lesions observed at Guy's hospital during seven years: There were of— Major and minor operations.... 1364 cases—tetanus occurred in 1 Wounds of all Varieties 594 " di9 Injuries and contusions 856 " I( di 1 Burns and scalds 458 " 44 61 Compound fractures 396 '' If9 Total 3668 23 From the large experience thus afforded, it appears that tetanus is most frequently met with in the more severe varieties of injury and accident, such as compound fractures, burns, and injuries to the fingers and toes. It is still a disputed point, whether the seat of the injury forms any special connection with the disease. Hennen, one of our great est authorities on military surgery, observed it oftener after wounds of the elbow and knee; others, again, more frequently from injuries of the thumb and great toe. There is certainly a popular belief that wounds of the ball of the thumb are especially likely to be followed by tetanus.