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630 professors of language in conference but by the whims of the man in the street, not because their derivation is impeccable but because they do their job better than their predecessors. So it must be with debridenaent. If it means relief of tension, as undoubtedly it does or rather did, do we need it at all ’? Is one long French word better than three short English ones ? ‘? Does it say anything new or describe anything old more clearly, more concisely or more beantifully z? If on the other hand it means all the steps of surgical wound sterilisation elaborated in the last war and practised, possibly with modifications, in this, as it undoubtedly did to the surgeons who developed that technique and to the majority of those who use it today, it becomes a useful and indeed an indispensable word. It saves time in writing and unnecessary repetition of technical details to those who are already familiar with them. These points will be settled eventually by the con- sensus of surgical opinion, and settlement will come easier and sooner if we admit that the word is no longer French, but has become part of the vocabulary of British surgeons. Let us remove the accent and drop the italics. As debridement it is our word, one that we can pronounce as we like and use to convey the meaning for which it is most needed without reference to the dictionary. ORIGINS OF HEADACHES Penfield z originally followed up the work of Foerster and others who have studied the mechanism of head- aches by stimulating the exposed brain, dura, and intracranial blood-vessels and noting the resulting sensations. Now, with MeN aughton2 he has investigated the anatomical background of his previous clinical and experimental observations. He found that the brain itself and the intracerebral blood-vessels were insensitive, but that the walls of the dural sinuses, the large intracranial arteries, and some areas of the dura were extremely sensitive. Pain produced by dural distortion-that, for example, due to pressure upon the falx and tentorium- was referred to a distance from the point of stimulation, while stimulation of the larger arteries caused local pain. Some areas of the meninges were more sensitive than others-for instance, stimulation of the posterior third of the falx caused severe pain, and the walls of the sinuses and points of entry of veins had a much greater sensitivity than the rest of the dura. Whether pressure, traction, heat, or electricity were used as stimulants the resulting pain had always the same quality ; it was, in fact, a headache, and was sometimes accompanied by nausea, vomiting and restlessness. The reference of the headache following local stimulation was usually ipsilateral, but was often far removed from the point of stimulation. For instance pressure upon the tentorium or upon the posterior part of the falx caused a frontal headache. The reference of this pain is explained by the anatomy of the nerve-supply of the cerebral dura mater, which is all, except for that in the posterior fossa, supplied by the trigeminal nerve. Fibres from the second and third division, and sometimes from the first, pass up with the middle meningeal artery to supply the lateral cranial walls, while the superior longitudinal sinus and falx are innervated mainly by the ophthalmic division via the tentorial and anterior ethmoid nerves. The tentorial nerve also supplies the superior wall of the transverse sinus, but its inferior surface and the dura of the posterior fossa receive a nerve-supply from the vagus, and also perhaps from the ninth and tenth cranial nerves. Although much of this area is very sensitive, nerve-end- ings are difficult to find, and their number varies from case to case. This may explain the wide individual variation found in the sensitivity of these structures. 1. Penfleld, W. Ass. Res. nerv. ment. Dis. Proc. 1935, 15, 399. 2. Penfield and McNaughton, F. Arch. Neurol. Psychiat. July, 1940, p. 43. Penfield and McNaughton also describe a series of cases where pain related to dural scars or deformity was relieved by denervation of the dural sinuses or by section of the appropriate division of the trigeminal nerve. They conclude that although headaches have been attributed variously to irritation of the dura, the meningeal and cerebral arteries, and the ventricular walls, the dura with its sinuses and tributary veins is the commonest site of origin. They suggest that treatment of intractable headache should not be abandoned until the pain mechanism has been studied in each case, and radical treatment has been undertaken to remove the local cause or, if necessary, to section the appropriate sensory nerves. EXTERNAL HYSTEROGRAPHY FoR many years obstetricians have been studying the action of the uterus in labour both from a physiological and a pathological standpoint. Most of this work has been done by careful clinical observation, but from time to time the aid of scientific recording instruments, of greater or less accuracy, has been invoked. The first hysterography studies are credited to Schatz 1 who introduced into the uterus a small rubber bag of 80 c.cm. capacity connected to a revolving drum. Chassar Moir 2 used this method to assess the action of the ergot alka- loids on the uterus, and thereby established the value of ergometrine. This internal method, has, however, four major disadvantages. First, it is a foreign body,, and like any foreign body introduced into a hollow viscus may set up unnatural contractions. Secondly, any foreign body introduced into the upper reaches of the birth-canal must, no matter how skilful the operator and how ideal the aseptic ritual, carry with it at least a small risk of infection. Thirdly, its introduction needs an anaesthetic which may itself influence uterine behaviour. Lastly, the use of internal apparatus requires an elaborate technique of sterilisation, skilled assistance and attention. These manifest disadvantages have led to the increasing use of an apparatus which is entirely external, first devised by Schaffer in 1896. This method is not ideal, since the record must take into account various extraneous movements such as abdominal respiratory excursions, aortic pulsation transmitted through the uterus, vomiting, and in fact any movement of the patient ; but these superimposed tracings are easily distinguished from the orderly sequence of the uterine contractions. A levered cork hammer is applied to the maternal abdomen by means of a circular base which carries a pneumatic chamber ; the hammer is connected to a rubber diaphragm in the pneumatic chamber, so that any excursion of the hammer is interpreted via a recording tambour on a smoked drum. When the uterus contracts the anteroposterior diameter of the uterus and the abdomen increases ; this results in an upward deflection of the hammer and compression of the air in the closed system, producing an upward stroke on the drum. The whole apparatus is light and rides comfortably on the patient, who is thus permitted a fairly wide range of normal movements. Mostyn Embry 3 has used this method to illustrate the effect of various drugs, notably in cases of inertia. He finds that gas administered by Minnitt’s apparatus does not depress uterine contractions but enhances the intensity of individual contractions and increases the tone of the uterus ; even when administered in concentrations suffi. cient to produce anaesthesia it has little or no depressant action. Ether used as an analgesic does not depress uterine action or retard labour, but when pressed to the point of anaesthesia the intensity of contraction is lessened and the interval between contractions is lengthened in direct proportion to the depth of the 1. Arch. Gynaek. 1872, 3, 58. 2. Proc. R. Soc. Med. 1935, 28, 1654. 3. J. Obstet. Gynœc. August, 1940, p.371.