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THE HISTOLOGY OF THE NEUROMUSCULAR JUNCTION Downloaded from https://academic.oup.com/brain/article/84/1/75/372729 by guest on 27 September 2021 IN DYSTROPHIA MYOTONICA

VIOLET MACDERMOT Department of Neurology, St. Thomas' Hospital, London, S.E.I

(1) INTRODUCTION DYSTROPJHC MYOTONICA is a familial disease affecting males and females, usually presenting in adult life, characterized by muscular wasting and weakness together with certain other features. The muscles mainly involved are the temporal, masseter, facial, sternomastoid and limb muscles, in the latter those mainly affected being peripheral in distribution. A widespread disorder of muscular contraction, myotonia, is also present but is noticed chiefly in the tongue and in the muscles involved in grasping. The other features of the condition are some degree of mental defect, dysphonia, cataracts, frontal baldness, sparse body hair and testicular atrophy. Any of the manifestations of the disease may be absent and the order of presentation of symptoms is variable. The myotonia may precede muscular wasting by many years or may occur independently. In those muscles which are severely wasted the myotonia tends to disappear. The interest of dystrophia myotonica lies in the peculiar distribution of muscle involvement and in the combination of a disorder of muscle function with endocrine and other dysplasic features. The results of histological examination of biopsy and post-mortem material have been described and reviewed by numerous workers, notably Steinert (1909), Adie and Greenfield (1923), Keschner and Davison (1933), Hassin and Kesert (1948), Wohlfart (1951), Adams, Denny-Brown and Pearson (1953), Greenfield, Shy, Alvord and Berg (1957). None of these investigators found conclusive evidence of involvement of the central nervous system. Examination of sections of muscle stained by usual methods showed in general that the characteristic feature of dystrophia myotonica was the presence of rows of centrally placed nuclei in otherwise intact muscle fibres. Other features such as atrophy and hypertrophy of muscle fibres, degeneration of muscle fibres, and increase in endomysial fibrous and fatty tissue appeared to be related to the later stages of the 76 VIOLET MACDERMOT

disease, and were not obvious in many cases. It was noted by Adams et al. (1953) and by Greenfield et al. (1957) that the muscle fibres were particu- larly liable to fixation artefact. • It is noteworthy that little mention was made of changes in the intramuscular nerve fibres until the introduction by Cogrs (1952a) of the intra- vital methylene-blue staining technique for muscle biopsy. In muscular dystrophy Bowden and Gutmann (1946) and Adams et al. (1953) found that the nerve fibres appeared normal. When the muscle fibres reached an advanced stage of degeneration, atrophic changes within the motor end- Downloaded from https://academic.oup.com/brain/article/84/1/75/372729 by guest on 27 September 2021 plates occurred, and finally with the disappearance of degenerate muscle fibres, long branches of the terminal nerve fibres were found ending blindly in the endomysial tissue. These workers used silver staining methods. Using the methylene-blue technique it was seen that abnormalities of the innervation pattern were present in dystrophia myotonica, which though similar to those seen in other myopathic disorders, showed certain characteristic features (Cogrs, 19526; Cogrs, 1955; Coers and Woolf, 1959). The nerve fibres within the intramuscular nerve bundles were said to be normal. The more distal nerve fibres were seen to show an unusual profusion of subtenninal nerve sprouts. The end-plates were noted to be large and well formed. Nerve fibres were described which ran parallel to muscle fibres and gave off short collateral sprouts. Another feature was the formation of a network of ramifying nerve fibres round individual muscle fibres. It is suggested that this axonal sprouting is secondary to the combined effects of degeneration and hypertrophy of the muscle fibres. In the present paper 10 cases of dystrophia myotonica are presented, the electromyographic and biopsy findings are described and an alternative suggestion is made as to the significance of the distal nerve changes.

(2) TECHNIQUES (a) The technique of muscle biopsy using intra-vital methylene-blue to stain nerve fibres is described in detail by Coers and Woolf (1959). In the present series the deltoid was selected for biopsy in all cases and two adjacent strips of muscle were removed. Paraffin embedded sections cut at a thickness of 5-10/* were stained with haematoxylin and eosin, hsematoxylin and Van Gieson, and a trichrome stain. In addition, in order to demonstrate intramuscular nerve fibresfurthe r sections were stained as described by Bodian (1937) and Romanes (1950). Photographs of these sections were taken. Since the methylene-blue stained sections were cut at a thickness of 50-100^, the course of the distal nerve fibres as they travel in three dimensions between the muscle fibres was extremely difficult to record photographically. Drawings were therefore made of these sections, recording the appearances as two-dimensional diagrams. (b) Electromyography was carried out as described by Bauwens (1955) selecting various muscles {see Table I). Using a concentric needle electrode the muscle was explored and the pattern of electrical activity recorded at rest, on minimum and on full volition. In two cases no electromyography was done and in one case no record was made of the pattern obtained on volition. NEUROMUSCULAR JUNCTION IN DYSTROPHIA MYOTONICA 77

TABLE I.—ELECTROMYOORAPHY Cases 1 2 3 6 7 8-9 10 Muscles Abductor Flexor Biceps Deltoid Abductor Tibialis Deltoid Extensor explored pollicis carpi polllcis anterior carpi brevis ulnaris brevis ulnaris

Biceps Extensor Flexor Brachio- Extensor Extensor digitorum carpi radialis digitorum digitorum communis ulnaris communis communis At rest High Downloaded from https://academic.oup.com/brain/article/84/1/75/372729 by guest on 27 September 2021 frequency discharges +++ + + + + + 0 On full volition Complete pattern +++ — + + + + Normal potentials + 00 — + 0 0 0 Reduced pattern 0 + 0— 0+ 0 + Low amplitude short duration potentials +++— 0 + + + NOTE.—Electromyography was not performed on Cases 4 and 5.

(3) DESCRIPTION OF CASES Case 1.—A male aged 18 years first noticed symptoms in his 14th year. His maternal grandmother and mother had cataracts. Examination showed bilateral ptosis, temporal wasting and facial weakness. In the upper limbs the tendon reflexes were absent and the grasp was myotonic. Case 2.—A male aged 35 first noticed symptoms in his 18th year. His father and two brothers had cataracts. Examination showed low intelligence, frontal baldness, testicular atrophy and bilateral cataracts. The muscular system showed bilateral ptosis, temporal wasting, facial and palatal weakness, wasting and weakness of the sternomastoids and trapezii, and percussion myotonia of the tongue. The limbs showed generalized muscle wasting and weakness with depression of tendon reflexes and marked myotonia of grasp. Case 3.—A male aged 36 was first noticed to show symptoms in his first decade. His sister and possibly a maternal uncle were similarly affected. Examination showed imbecility, frontal baldness, absence of body hair, and a feminine distribution of fat, testicular atrophy, and bilateral cataracts. The muscular system showed temporal wasting, facial weakness, wasting and weakness of the sternomastoids and trapezii and wasting of the tongue. The limbs showed generalized muscle wasting and weakness most marked peripherally, with bilateral foot drop and absent tendon reflexes. The grasp was myotonic. Case 4.—A female aged 43, sister of Case 3, was probably first noticed to show symptoms in her second decade. Examination showed feeble-mindedness, frontal baldness, scanty body hair. There was facial weakness and wasting and weakness of the sternomastoids. The limbs showed generalised weakness most marked peripherally. The tendon reflexes were almost absent and the grasp was myotonic. 78 VIOLET MACDERMOT

Case 5.—A female aged 44 was probably first noticed to show symptoms in her second decade. Her father, two paternal uncles and two brothers were similarly affected. Examination showed feeble-mindedness, frontal baldness. There was facial weakness and wasting and weakness of the sternomastoids. The limbs showed slight peripheral wasting and weakness, absent tendon reflexes and percussion myotonia of the thenar eminences. Case 6.—A male aged 49 first noticed symptoms in his 27th year. 6 out of his 9 brothers were similarly affected. Examination showed a speech defect, frontal

baldness, feminine distribution of fat and body hair, bilateral cataract. There was Downloaded from https://academic.oup.com/brain/article/84/1/75/372729 by guest on 27 September 2021 facial weakness and wasting and weakness of the sternomastoids. The limbs showed peripheral wasting and weakness with absent tendon reflexes and a myotonic grasp. There was marked weakness of the trunk muscles. Case 7.—A female aged 50 first noticed symptoms in her third decade. No members of her family were known to be affected. Bilateral cataracts were removed at 33 years of age. Examination showed weakness of phonation, bilateral ptosis, temporal wasting, facial weakness, palatal weakness, wasting and weakness of the sternomastoids and myotonia of the tongue. The limbs showed generalized weakness most marked peripherally, with absent tendon reflexes and a myotonic grasp. There was weakness of the trunk muscles. Case 8.—A male aged 58 first noticed symptoms in his 44th year. No members of bis family were known to be affected. Examination showed low intelligence, weakness of phonation, frontal baldness, testicular atrophy, bilateral early cataract. The muscular system showed temporal wasting, facial weakness, wasting and weakness of the sternomastoids and posterior cervical muscles, and percussion myotonia of the tongue. The limbs showed generalized wasting and weakness with bilateral foot-drop, absent tendon reflexes and a myotonic grasp. The trunk muscles were weak and there was a thoracic kyphoscoliosis. Case 9.—A female aged 58 first noticed symptoms in her 26th year. No members of her family were known to be affected. Examination showed sparse hair on her head and body with a coarse dry skin, weakness of phonation, bilateral early cataracts. The muscular system showed bilateral ptosis, temporal wasting, facial weakness, and wasting and weakness of the sternomastoids. The limbs showed generalized wasting and weakness most marked peripherally and most marked in the upper limbs. The tendon reflexeswer e depressed and the grasp was myotonic. Case 10.—A female aged 61 first noticed symptoms in her 39th year. Her mother, two brothers, one sister and three daughters were similarly affected. Bilateral cataracts were removed at 46 years of age. Examination showed weakness of phonation, bilateral ptosis, temporal wasting, facial weakness, and wasting and weakness of the sternomastoids. The limbs showed generalized wasting and weakness most marked peripherally with depression of the tendon reflexes. The grasp was myotonic and there was percussion myotonia of the thenar, thigh and anterior tibial muscles.

(4) HISTOLOGY Paraffin Embedded Sections {see Table II) Variation in muscle fibre calibre was diffuse and was very slight in Case 1, consisting of occasional atrophic fibres. In Cases 3 and 4 the degree of variation was marked and a number of hypertrophic muscle fibres were present in addition to atrophic fibres. In the remainder of the cases the degree of variation was moderate {see figs. 14 and 15). NEUROMUSCULAR JUNCTION IN DYSTROPHIA MYOTONICA 79

TABLE n.—PARAFFIN-EMBEDDED SECTIONS Cases 12 3 456789 10 Variation in calibre of musdefibres .. .. + ++ + + + + + + ++ ++ ++ ++ ++ + + Increased number of subsarcolemmal nuclei .. + + + + + + + + + + ++ ++ ++ ++ ++ + + + Central position of subsarcolemmal nuclei .. + + + + + + + + + + ++ ++ ++ ++ ++ + + + Chain formation by nuclei + + + + + + + + + + ++ ++ ++ ++ ++ + + + Groups of nuclei ..0+ + + 00+00 + Basophilic staining of Downloaded from https://academic.oup.com/brain/article/84/1/75/372729 by guest on 27 September 2021 muscle fibres .. ..+ + + + ++0+ 0 Degeneration of muscle fibres + + + + ++0 0 0 Increase of interstitial cells 00 0 0 00000 Increase of endomysial fibrous tissue .. ..0 + ++ ++++0 + 0 + Increase of endomysial fatty tissue .. ..0 + + ++++0 Small calibre nerve fibres.. + +

Increase in number, central location and chain formation of subsarcolemmal nuclei was the most striking abnormality in all cases. In Cases 2, 3, 4 and 7 this occurred to a marked degree. In the remainder of the cases it was less frequent and in Case 1 occurred only occasionally. Groups consisting of a dozen or more nuclei, sometimes in relation to an atrophic muscle fibre were seen in Cases 2, 3, 4, 7 and 10 but were not frequent (see figs. 12, 13 and 15). Basophilic staining and degenerative changes occurred in occasional scattered muscle fibres in all except Cases 7 and 8. In no case were these changes marked. A slight increase in number of interstitial cells was seen in Case 10 only. In Case 1 "ring fibres" as described by Heidenhain (1918) were seen. Increase in endomysial fibrous or fatty tissue was not a marked feature in any case and was not seen in Cases 1 and 6. In Cases 8 and 10 there was slight increase of fatty tissue without fibrosis. In the remainder of the cases some degree of fibrous and fatty tissue increase was seen. Intramuscular nerve fibres were seen in all cases, and in all cases, even using routine staining methods, these nerve fibres appeared to be of unusually small calibre. Using silver stains it could be seen that both the axons and myelin sheaths, when compared with normal controls, were involved in this reduction in calibre. The distal irregularities of the axons were also seen with these methods. There was no obvious increase in the fibrous tissue of the perineurium of these fibres (see figs. 16 and 17).

Methylene-blue Stained Sections (see Table US) Abnormalities of the axons and myelin were seen in all cases to be present both in the distal nerve fibres and also in the intramuscular nerve bundles. The axons •in some places showed deeply staining swellings 80 • VIOLET MACDERMOT

TABLE HI.—METHYLENE-BLUE STAINED SECTIONS Cases 12 3 4 56789 10 Abnormal swellings of axons and myelin .. + Abnormal tortuosity of • fibres .. .. 0 Abnormal branching of fibres .. .. 0 Abnormal length of fibres .. .. 0 Fine beaded fibres .. 0 Downloaded from https://academic.oup.com/brain/article/84/1/75/372729 by guest on 27 September 2021 Abnormally large end- plates .. .. + Abnormally small end- plates .. .. + Abnormally elongated end-plates .. .. + Ultra-terminal fibres.. 0 Profuse terminal branching with multiple end-plates +

which were globular or elongated and in other places the calibre of the nerve fibres was greatly reduced {see figs. 1, 2, 5, 8, 9 and 10). In addition swellings of the myelin were seen which stained less densely than the axonal swellings (see figs. 2, 5 and 10). In places breakdown of fibre substance occurred. Abnormal tortuosity of nerve fibres was a feature in all except Case 1. In Case 3 this was marked and was often associated with complex terminal branching (see fig. 4). A marked increase of nerve fibre branching, other than that which occurred pre-terminally in relation to the end-plates, was not a feature except in Case 3. In this case extremely complex branching occurred both distally and more proximally. A few abnormally long nerve fibres were seen in all cases, usually running parallel to the muscle fibres. Fine beaded fibres were seen in all cases (see fig. 8). There was considerable variation in the size and appearance of motor end-plates, the majority being abnormally small (see figs. 4, 5 and 6). Large straggling end-plates were seen in all except Cases 2, 4 and 7 (see figs. 8, 9 and 10). Elongated end-plates, running parallel to muscle fibres were seen in all cases (see figs. 4, 7, 8 and 9). Ultra-terminal fibres were not frequent. The striking feature of the majority of the cases was the extremely profuse terminal branching of the nerve fibres, with the formation of multiple end-plates on the same muscle fibre (see figs. 3, 4, 7 and 8). In some cases anastomosis appeared to occur between the pre-terminal nerve fibres to form a network on the surface of the muscle fibres. NEUROMUSCULAR JUNCTION IN DYSTROPHIA MYOTONICA 81

(5) DISCUSSION The 10 patients presented all showed the typical clinical features of dystrophia myotonica. The duration of symptoms referable to the muscular system ranged from four years in Case 1 to thirty-two years in Cases 9 and 10. In the majority, symptoms had been present for more than twenty years. Except for Case 1, all showed some degree of weakness of the deltoid, though weakness of the peripheral muscles was more marked. All showed a myotonic grasp. All led fairly restricted lives Downloaded from https://academic.oup.com/brain/article/84/1/75/372729 by guest on 27 September 2021 except Case 1. Case 3 was bedridden. Electromyography of various muscles showed the presence, in all the cases tested, of high frequency discharges at rest (see Table I). In Case 10, discharges were obtained from one of the muscles tested but not from the other. On full volition a complete pattern was found in all cases in at least one of the muscles tested. In two cases this pattern was composed of normal potentials in at least one of the muscles tested. In the remainder, the potentials were of low amplitude and short duration. In Case 1 a normal pattern was obtained from one part and a myopathic pattern from another part of the same muscle. In three cases one of the muscles tested showed a reduced pattern. The degree of clinical weakness, in some cases, appeared greater than would have been expected from the electromyographic record. The histological findings in the routine stained sections were the changes characteristic of dystrophia myotonica. As described by previous workers, there was relatively little degeneration of muscle fibres. The degree of fibre atrophy, except in Cases 2, 3 and 4 was not marked. The typical appearance of the subsarcoleinmal nuclei was seen in all cases, but in all except four cases the degree was not marked. In Case 1 the degree of abnormality was very slight. Increase in fibrous or fatty tissue was in no case marked. Intramuscular nerve bundles were seen in all cases and in all, even using routine stains, the calibre of the nerve fibres was unusually small. This appearance was seen more clearly using silver stains when the axons appeared abnormally slender. Counter-staining of the myelin sheaths showed that they also were unusually thin. Methylene-blue stained sections showed profuse terminal branching of the nerve fibres as described by Coers (19526 and 1955) and Coers and Woorf (1959), together with anastomosis of nerve fibres on the surface of muscle fibres, and the presence of abnormally large and small motor end- plates. In addition to these distal abnormalities, a striking feature was the abnormal appearance of the axons and myelin which extended proximally and was seen in the intramuscular nerve bundles. Swellings and irrgu- larities of the axons and myelin were seen in some places. In other places there was marked reduction of calibre and even complete breakdown of nerve fibre substance. It is possible that the abnormal appearance of the distal neurone in

6 BRAIN—VOL. LXXXTV 82 VIOLET MACDERMOT dystrophia myotonica may be secondary to changes in the muscle fibres. An alternative suggestion is that it represents a primary defect of the distal neurone. In favour of this view is the fact that there was little obvious breakdown of muscle fibre substance in the majority of the cases presented {see Table H). Some of the patients were rather weaker than might have been expected from the electromyographic findings and the histological appearance of their muscles. The weakness did not appear to be related to clinical myotonia. In Case 1, in whom myotonia of grasp was the only symptom, there was no weakness, no electromyographic abnormality other Downloaded from https://academic.oup.com/brain/article/84/1/75/372729 by guest on 27 September 2021 than myotonic discharges, and the muscle fibres were mainly normal, yet the distal nerves showed considerable abnormality. It is unlikely that increase in fibrous tissue is contributory, since this was not marked in any case and was absent in Case 1. Investigations on myotonia have suggested that this phenomenon is due to abnormality of the muscle fibres themselves Brown and Harvey (1939), in goats with congenital myotonia, found that the myotonia persisted after nerve section or curarisation. In man it was found not to be abolished by intra-arterial curare (Lanari, 1946; Landau, 1952) or by the intravenous administration of d-tubocurarine 10 mg. or decamethonium 1-5 mg. (Geshwind and Simpson, 1955). The evidence presented in this paper suggests that, in addition to a muscle fibre abnormality, there is also a neuronal defect in dystrophia myotonica.

(6) SUMMARY (1) The literature relating to the histology of the peripheral nerves and muscle in dystrophia myotonica is briefly reviewed. (2) 10 cases of dystrophia myotonica are presented in whom muscle biopsy, using silver and methylene-blue staining techniques in addition to routine methods, was performed. (3) Attention is drawn to the abnormalities seen in the nerve fibres within the intramuscular nerve trunks in addition to those found in the distal nerve fibres and motor end-plates. (4) The electromyographic findings are described. (5) The significance of the histological changes is discussed and a suggestion is made that, in addition to a disorder of muscle in dystrophia myotonica, there is also a neuronal defect.

ACKNOWLEDGMENTS I wish to thank Dr. J. St. C. Elkington and Dr. R. E. Kelly for encourage- ment with this investigation and for permission to publish cases admitted under their care. I am grateful to Dr. P. Bauwens for help and for permission to publish the electromyographic records and to Professor R. C. Curran for facilities in the Department of Pathology, St. Thomas's Hospital Medical School. I wish to thank Mr. A. E. Clark for the photo- NEUROMUSCULAR JUNCTION IN DYSTROPHIA MYOTONICA 83, micrographs, Mr. T. W. Brandon for photographic reproduction of the diagrams, and Mr. A. H. Spicer for the histological preparations. I am indebted to Dr. A. L. Woolf for helpful criticism of the manuscript. REFERENCES ADAMS, R. D., DENNY-BROWN, D., and PEARSON, C. M. (1953) "Diseases ofMuscle." London, pp. 248-278. ADIE, W. J., and GREENFIELD, J. G. (1923) Brain, 46, 73.

BAUWENS, P. (1955) Proc. R. Soc. Med., 48, 194. Downloaded from https://academic.oup.com/brain/article/84/1/75/372729 by guest on 27 September 2021 BODIAN, D. (1937) Anat. Rec, 69, 153. BOWDEN, R. E. M., and GUTMANN, E. (1946) Arch. Neurol. Psychiat., Chicago, 56, 1. BROWN, G. L., and HARVEY, A. M. (1939) Brain, 62, 341. COERS, C. (1952a) /. Neurol. Neurosurg. Psychiat., 15, 211. (1952*) Ada din. belg., 7, 407. (1955) Ada neurol. belg., 55, 741. , and WOOLF, A. L. (1959) "The Innervation of Muscle." Oxford, pp. 107-112. GESHWIND, N., and SIMPSON, J. A. (1955) Brain, 78, 81. GREENFIELD, J. G., SHY, G. M., ALVORD, E. C, and BERG, L. (1957) "An Atlas of Muscle Pathology in Neuromuscular Diseases." Edinburgh and London, pp. 80-81. HASSIN, G. B., and KESERT, B. (1948) /. Neuropath., 7, 59. HEIDENHAIN, M. (1918) Beitr. path. Anat., 64, 198. KESCHNER, M., and DAVISON, C. (1933) Arch. Neurol. Psychiat., Chicago, 30, 1259. LANARI, A. (1946) Science, 104, 221. LANDAU, W. M. (1952) Neurology, 2, 369. ROMANES, G. J. (1950) /. Anat., Lond., 84, 104. STEINERT, H. (1909) Dtsche. Z. Nervenheilk, 37, 58. WOHLFART, G. (1951) /. Neuropath., 10, 109.

LEGENDS TO PLATES PLATE LX FIG. 1 (Case 1).—Swellings of axons. Variation in calibre of nerve fibres. (Methylene-blue.) Fio. 2 (Case 2).—Swellings of axons and myelin. Variation in calibre of nerve fibres. (Methylene-blue.) FIG. 3 (Case 3).—Complex terminal branching. (Methylene-blue.) FIG. 4 (Case 4).—Tortuous nerve fibres. Complex terminal branching. Elongated end-plates and small end-plates. (Methylene-blue.)

PLATE X FIG. 5 (Case 5).—Swellings of axons and myelin. Small end-plates. (Methylene-blue.) YiG^^Case 6).—Small end-plates. (Methylene blue.) FIG. 7 (Case 7).—Complex terminal branching. Elongated end-plates. (Methylene-blue.) FIG. 8 (Case 8).—Swellings of axons and myelin. Fine beaded fibres. Large end- plates and elongated end-plates. (Methylene blue.) 84 VIOLET MACDERMOT

PLATE XI FIG. 9 (Case 9).—Swellings of axons. Large end-plates and elongated end-plates. (Methylene-blue.) FIG. 10 (Case 10).—Swellings of axons and myelin. Variation in calibre of fibres. Large end-plates. (Methylene-blue.) FIG. 11 (Control).—Normal innervation pattern. (Methylene-blue.)

PLATE XII Downloaded from https://academic.oup.com/brain/article/84/1/75/372729 by guest on 27 September 2021 FIG. 12 (Case 2).—Occasional atrophic muscle fibres. Increase in number of subsarcolemmal nuclei with chain formation. (Hsematoxylin and eosin. x 140.) FIG. 13 (Case 2).—Chain formation by subsarcolemmal nuclei. (Hsematoxylin and eosin. X28O.) FIG. 14 (Case 1).—Slight variation in muscle fibre calibre. (Haematoxylin and eosin. X140.) FIG. 15 (Case 5).—Moderate variation in muscle fibre calibre, increase in number, and central location of subsarcolemmal nuclei. (HEematoxylin and eosin. x 140.) FIG. 16 (Case 5).—Intramuscular nerve bundles showing abnormally fine calibre nerve fibres. (Bodian stain, x 280.) FIG. 17 (Control).—Normal intramuscular nerve bundle. (Bodian stain. X280.) PLATE IX Downloaded from https://academic.oup.com/brain/article/84/1/75/372729 by guest on 27 September 2021

FIG. 1. FIG. 2.

FIG. 3. FIG. 4.

To illustrate article by Violet MacDermot. PLATE X Downloaded from https://academic.oup.com/brain/article/84/1/75/372729 by guest on 27 September 2021

FIG. 5. FIG. 6.

FIG. 7. FIG. 8.

To illustrate article by Violet Mac Dermot. PLATE XI Downloaded from https://academic.oup.com/brain/article/84/1/75/372729 by guest on 27 September 2021

FIG. 9. FIG. 10.

FIG. 11.

To illustrate article by Violet MacDermot. PLATE XH Downloaded from https://academic.oup.com/brain/article/84/1/75/372729 by guest on 27 September 2021

FIG. 12. FIG. 13.

FIG. 14. FIG. 15.

FIG. 16. FIG. 17.

To illustrate article by Violet MacDermot.