A "Lazy-tongs" Brain-lesion Localizer (a Surgical Instrument).
Year: 1895

page_text: Date of Application, 13th Mar., 1895
Complete Specification Left, 12th Dec., 1895-Accepted, 29th Feb., 1896
PROVISIONAL SPECIFICATION.
A "Lazy-tongs" Brain-lesion Localizer (a Surgical Instrument).
I, ROBERT HANHAM Cox 86 Clanbrassil Street Dundalk, Ireland, Physician
and Surgeon, do hereby declare the nature of this invention to be as follows:-
The application of the "lazy-tongs" mechanism for the purpose of localizing
brain-lesions on the overlying surface of the skull.
The instrument consists of a metal "lazy-tongs" ring sufficiently large, when
expanded, to surround the human skull, and having rivetted, to its outer side, at
four equidistant points, the ends of two lengths of the like ("lazy-tongs") long
enough to arch, when extended, across the skull, from before backward in the case
of the one, and from side to side in the case of the other-one length having a letter
on each of the central rivets, and the other a number.
Dated this Eleventh day of March 1895.
joined together as shown hereafter.
(1.) The circular band consists of metal lazy-tongs in the form of a circle, having
twenty eight fenestrae, and being sufficiently large, when extended to surround the
human skull.
(2.) The longitudinal band is of the like lazy-tongs with twenty two fenestræ
having the central rivets, excepting the first, engraved with the letters A @ V in
consecutive order from the second to the twenty second, inclusive. This longi-
tudinal band is attached by two of its central rivets-the first and that bearing the
letter T-to two opposing central rivets of the circular band, in such a way that
the longitudinal band arches over, and outside of, the circular band, while the
portion from the fixed rivet T to the end is continued free.
(3.) The latitudinal band is of the like lazy-tongs, with twenty fenestra.
Nineteen of the central rivets being engraved with the numerals, beginning (at the
second rivet from each end) with 1 and ending in the middle with 10. This band
is attached to the circular band, by its first rivets at each end, to the opposing
central rivets equidistant from the junctions of the longitudinal band, so that it
arches over the circular band from side to side, and also over, and at right angles
to, the longitudinal band.

page_text: To use the instrument it is necessary to extend it in all parts and apply it to the
human head with the rivet, forming the junction of the longitudinal band with the
circular band and below that marked A, on the root of the nose; and the rivet
marked V, at the extreme end of the same longitudinal band is applied to the
occipital protuberance; when the band between these two points should be pressed
down to the skull in the middle, or antero-posterior, line; while the circular band
is also closed on the skull on such a plane that the central rivet, bearing the
numeral 10, of the latitudinal band, may rest on the middle line as shown by the
longitudinal band. The instrument is thus fixed to the skull by both the circular
and longitudinal bands; while the latitudinal band may be moved backwards and
forwards with a hinge-like action, when each numbered rivet will describe a semi-
circle of latitude; and the portion of the same band, from one of the fixed rivets to
the numeral 10, will give the radius of longitude.
Thus, the surface of the brain having been mapped out on the cadaver by this
same instrument into degrees of latitude and longitude and a map made, the
corresponding points on the living head can readily be obtained, the latitude and
longitude being known, by placing the numeral 10 on the letter of longitude, when
the numeral of latitude will rest over the part sought for.
The drawing (Fig. 1.) shows the instrument extended. A B C D is the circular
band. F A C is the longitudinal band. B D is the latitudinal band.
The small letters and numerals shown represent those on the corresponding
central rivets of the longitudinal and latitudinal bands. These two bands have
each a hinge-like motion on the rivets attaching them to the circular band, at A-C
and B-D, respectively; thus the part bearing of the former can be moved nearly
as far as the points B, on the one side, and D, ou the other side (till hindered by
the overlying latitudinal band); while the part bearing 10 of the latter (latitudinal
band) can be moved forward to C, and backward to A, or even F. The movement
of this latter band is alone made use of.
The instrument is applied to the head with the point F on the occipital
protuberance and the point C on the root of the nose. With the instrument in
position, location is performed thus:-From a list of indices of the bearings of the
important parts of the cerebral cortex, made by the aid of this same instrument in
the same position on the cadaver with one side of the brain exposed, the index for
the part sought is taken; for example, say the centre for speech, given as
C left side." Now, if the latitudinal band be moved forward till the 10 at its
middle rests on the c of the longitudinal band, the numeral 4 on the left side will
rest over the centre for speech.
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Fig. 2. is a map, on a gnomonic projection, of the surface of one hemisphere of
the brain, made (with the aid of the above instrument) from a cast of the brain
in situ. It shows the principal fissures and convolutions; bars of bone corresponding
to the coronal, lambdoid and squamous sutures and the temporal ridge; also the
lines of latitude and longitude corresponding to the engraved rivets of the
instrument. It may be used with, or instead of, the list of indices above mentioned.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is performed, I declare that what I
claim is :-
The application of the lazy-tongs mechanism for the purpose of localizing brain
lesions and cerebral centres on the overlying surface of the human head.
Dated this Sixth day of February 1896.
ROBERT H. COX.