In one of our cases, a girl A., suffering from a nodding and rotatory tic of the head, examination of the cervical region revealed the existence of a line of cicatrices along the margin of the sternomastoid, the vestiges of a previous operation for a severe tuberculous adenitis. Some nerve filaments entering the sternomastoid and trapezius had no doubt been cut, since these muscles presented a minor degree of atrophy, and the irritation arising therefrom, as well at that due to dragging on the adhesions between the cicatrices and the underlying tissues, had been the starting-point of a motor reaction primarily convulsive and involuntary, but eventually habitual and automatic, and therefore, with the subsidence of the excitation, a tic.

In another case[78] a month's systematic treatment served to curtail to a noteworthy extent spasmodic head movements resembling those one makes to get rid of a fly.

From another point of view, some of the tics of this class are merely the exaggeration of certain functions destined for the expression of the ideas of affirmation and negation. The nod of the head with which little G. used to punctuate his "yes's" was logical enough, but he soon began its repetition irrespective of his topic of conversation, and even when saying "no"—a veritable tic of affirmation.

Numbers of people are in the habit of emphasising their words with those to-and-fro movements of the head that we call gestures of approval. Now, if the gesture be strictly appropriate to the thought present in the mind, it cannot be identified with the tics. On the other hand, its execution may be inopportune, in which case, provided the form remain normal, it is merely a stereotyped act, and must exhibit the additional features of abruptness and exaggeration ere it rank as a tic.

It is chiefly among the mentally infirm, such as idiots and imbeciles, that the phenomenon of salutation occurs, and as its rhythm is an element which is foreign to most ordinary tics, it is not likely to be confounded with them.

These conditions apart, however, there is one highly specialised clinical type that merits separate study—viz. mental torticollis.

MENTAL TORTICOLLIS

The medical world has long been familiar with various kinds of permanent or intermittent torticollis presumably unconnected with muscular, articular, or osseous lesions of the neck, and been as long divided on the question of their tabulation.

Instances of this affection, bearing such widely differing names as "hyperkinesis of the accessory of Willis," "spasmodic torticollis," "functional spasm of the neck muscles," "rotatory tic," etc., have abounded in medical literature ever since the days of Duchenne of Boulogne, Trousseau, and Charcot. Some twelve years ago now, the term mental torticollis was applied by Brissaud[79] to a type of convulsion of the neck musculature whose association with psychical disturbances justified its description as a tic, and his opinions have been abundantly confirmed by later observation.

As a matter of fact, mental torticollis is a tic which the patient can ordinarily curb by some procedure of his own invention. It has its raison d'être in his mental imperfection. To obviate misunderstanding, we must premise that the latter term is not synonymous with mental alienation. It merely signifies that lack of mental balance, to whatever extent, that is patent in all sufferers from tic.