The influence of changes in the intraocular circulation on the intraocular pressure / by E.E. Henderson, F.R.C.S., and E.H. Starling, F.R.S. (from the physiological laboratory, University College).

  • Henderson, E. E.
Date:
[1904?]
Catalogue details

Licence: In copyright

Credit: The influence of changes in the intraocular circulation on the intraocular pressure / by E.E. Henderson, F.R.C.S., and E.H. Starling, F.R.S. (from the physiological laboratory, University College). Source: Wellcome Collection.

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    of the first and second branches caused at first a rapid fall, followed by a rise. He does not mention whether the central end of the nerve was divided or how he prevented spread of current, nor do any blood-pressure tracings accompany the paper. Yon S c h u 11 e n <4), who condemns previous experiments on this subject, admits that in his own experiments many were worthless owing to the bleeding and other operative difficulties. He found that division of the 5th produced no considerable effect on the intraocular pressure. He gives a detailed experiment in which a marked rise of pressure took place as a result of stimulating the cut 5th nerve, but does not accompany his paper with any tracing of the blood-pressure. It is therefore impossible to judge whether or not he had any escape of current to adjoining tissues which might cause a simultaneous rise in blood-pressure. All our successful experiments on the action of the 5th nerve were performed on cats, since this nerve is much more accessible in these animals. Endeavours to expose the Gasserian ganglion in the dog were unsuccessful, owing to the severity of the operation required. In the cat the skin and temporal muscle were turned back from one half of the skull. The skull was opened by means of a trephine, and the skull cap removed between the superior longitudinal and lateral sinuses, the bone being removed as far down as the tentorium behind, and as the zygoma in front. The dura mater was not opened. Plugs of cotton¬ wool were now packed carefully into the cranial cavity between the dura and the skull, and the animal was left for 5 to 10 minutes. During this time the fluid is gradually squeezed out of the cerebral hemisphere on the operated side, and on now removing the cotton-wool it is possible to retract the brain and expose to view the upper surface of the petrous portion of the temporal bone, with the Gasserian ganglion lying on it beneath a thin layer of dura mater. At this stage bleeding may be troublesome, but may be largely avoided by a temporary ligature round the carotids, which can be drawn on as required. In some cases we managed to obtain a clear view of the ganglion by raising the animal’s head, so diminishing the oozing from the venous sinuses which surround the ganglion. The proximal end of the 5th as it entered the ganglion was then hooked up and divided between ganglion and brain. It is easy in this part of the operation to miss some of the fibres, so that the ganglion is left connected to a certain extent with the central nervous system. Such a mishap is at once revealed on stimulating the ganglion, by the reflex rise of blood-pressure that occurs. Needle electrodes were then thrust into the ganglion and