ON THE PRESENCE O F GANGLION CELLS I N THE THIRD AND SIXTH NERVES O F MAN

HELEN NICHOLSON Department of Anatomy, Universi ty of Eansas

FOUR FIGURES

The presence of sensory fibers in the third, fourth, and sixth nerves is described by Huber ('99) and later by Sher- rington and Tosier ('10). The latter authors, in their work upon the cat, rabbit, and monkey, give experimental evidence that these sensory fibers are not derived from either the sec- ond or fifth nerves, but are incorporated within the eye-muscle nerves themselves. Clinical evidence that they are in no way connected with the fifth nerve is presented by Harrison ( '09). That the ocular muscles have a definite spatial sense in visual perception and must, therefore, contain sensory fibers is held by Sherrington ('18).

Nicholls ('15) has reported the finding of fifteen ganglion cells on a single root of the third nerve in Scyllium canicula. He describes them as being a scattered group of cells situated about 1.4 mm. from the superficial origin of the nerve and extending f o r a distance of about 0.2 mm.

Both clinical and experimental evidence, theref ore, as well as the evidence from comparative anatomy creates a strong presumption that there is a sensory component in the eye- muscle nerves of man.

In the writer's investigations the brain of a full-term human foetus was removed and the roof of the orbit chipped away. The contents of the left orbit were removed entire, with the eyelids and fascia. This entire mass was embedded in cel- loidin and cut in serial sections, 40 p in thickness in the hori-

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zontal plane. The original order of the sections was carefully preserved. Each section was individually stained with hae- matoxylon and eosin.

The result of the technical procedure was better than oiie would expect, when the size of the object is taken into con- sideration. Red and white blood corpuscles can readily be distinguished in the blood vessels. Also the smaller blood vessels within the nerves and even the lymphatics can easily he traced. The cross striations of the muscle fibers are clearly differentiated.

The root of the left third nerve was the only one obtainable. I t was removed with a piece of the brain still attached, em- bedded in paraffin, cut in serial sections of 10 in thickness, and stained with haematoxylon and eosin.

Thirty scattered ganglion cells were counted on the root of the third nerve. They are situated along the margin of the fasciculi for a distance of about 1 mm. The most proximal cells are about 2.8 mm. from the superficial origin of the nerve, while the most distal ones are about 4 mm. out on the fibers. Each ganglion cell is surrounded by a typical connective-tissue capsule. The cells are relatively round in section and are either bipolar or unipolar. Their granular cytoplasm stains red in eosin. The nuclei stain purple and the chromatin ap- pears in granules and in relatively large masses. A compara- tively large nucleolus is found in each nucleus. The cells measure from 30 to 35 p in diameter. Their mean diameter is fourid to be about 23.5 p.

Four ganglia have been found on the lower division of the third nerve within the orbit. The relative positions of these ganglia are shown in figure 1, which represents the lower half of the orbit drawn somewhat schematically from projections of the serial sections. Three of these ganglia are on the branch to the inferior oblique muscle. The other is 011 the haiich to the internal rectus muscle. These ganglia contain approximately the following number of cells : ganglion num- ber 4, five cells ; ganglion 3, three cells ; ganglion 5, four cells, and ganglion 2, two cells. The total number of cells, there- fore, found on the third nerve within the orbit is fourteen.

2 3 Fig. 1 Schematic projection of the lower half of the human orbit, showing

the relative position of the ganglia I, 2, 3, 4, and 5 found on the eye-muscle nerves within the orbit.

Camera-lucida drawing of the ganglion cells found on the root of the third nerve, showing the position of the nerve cells in relation to the fasciculi.

Camera-lucida drawing of ganglion number 3, in figure 1, on the third nerve, showing the cells as they a re situated in a ganglionic group among the nerve fibers, surrounded by a network of richly nucleated connective tissue.

Fig. 2

Fig. 3

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34 HELEN NICHOLSON

No ganglion cells were found on either of the branches sup- plying the inferior and the superior recti muscles, although these branches were examined in detail.

The cells found in these ganglia within the orbit are not scattered along the fibers as they are on the roots of the

Fig. 4 Camera-lucida drawing of the ganglion found on the sixth nerve, show- ing the position of the ganglion within the connective-tissue sheath surrounding the nerve.

nerve, but are grouped together along the margin of the nerve trunk in a ganglion formation. The cells are surrounded by a network of richly nucleated connected tissue. I n size and shape the cells are like those found on the root of the nerve.

It is situated along the medial margin of the nerve, just as it enters

One ganglion has been found on the sixth nerve.

GANGLIA ON EYE-MUSCLE NERVES 35

the orbit. It contains approximately thirty cells. There is difficulty in determining the exact number of cells on account of the thickness of the sections.

Figure 4 is a camera-lucida drawing of this ganglion. These cells measure 20.5 p in diameter and are slightly smaller than those found on the third nerve.

It is noteworthy that the ganglion on the sixth nerve is in the nerve sheath (fig. 4), while the ganglia on the third nerve are on the inner side of the nerve sheath among the nerve fibers (fig. 3). The number of cells in the ganglia on the third nerve within the orbit is much less than the number found in the single ganglion on the sixth nerve, there being fourteen cells in the ganglia on the third nerve, while the ganglion on the sixth nerve contains thirty cells. A total num- ber of forty-four ganglion cells has been found on the entire third nerve.

No ganglion cells were found on the trunk of the fourth nerve, although this nerve was followed out with great care and detail through all of the sections. Investigation was not made upon the intracranial roots of the sixth and fourth nerves, as they were lost in the removal of the brain.

SUMMARY

The finding of ganglion cells on the root of the third nerve of the child confirms the observations of Thomsen ( '87) and is not a new discovery. But so far as it is known, no one has described the presence of ganglion cells on the eye-muscle nerves within the human orbit or in the orbit of any other animal. The finding of approximately thirty cells in the ganglion on the sixth nerve coincides with the results of Sher- rington and Tozier ( '10) in their degeneration experiments on the monkey, cat, and rabbit. They found that, upon intra- cranial severance of the sixth nerve, a few nerve fibers, about twenty in number, remained sound in the external rectus muscle. The finding of a ganglion on the trunk of this nerve explains the reason for the presence of these sound fibers. Also, they found that upon the intracranial severance of the

36 HELEN NICHOLSON

third nerve, a few sound fibers remained in each muscle which that nerve supplies. Most of these were found in the inferior oblique muscle. It is upon this branch of the nerve that I have found the largest number of ganglion cells (thirteen), while on the branch to the internal rectus muscle there are onlv two cells present.

This close correspondence of the relative number of cells here described on the nerves to different muscles with the number of sound nerve fibers persisting in the muscles inner- vated by these nerves in the operated animals of Sherrington and Tozier strongly corroborates the histological evidence that these cells are sensory.

The author wishes to express her appreciation to Prof. G. E. Coghill and Prof. H. C. Tracy for advice during the progress of this work and to Prof. Elise Neuen Schwander, of the University of Kansas, for generous assistance which has made the completion of this work possible.

BIBLIOGRAPHY

GASICELL, W. H. 1889 On the relation between the structure, function, distribu- tion, and origin of the cranial nerves; together with a theory of the origin of the nervous system of Vertehrata.

HARRISOX, P. W. 1909 An effort to determine the sensory path from tlie ocular muscles.

IIUBER, G. CARL A ndte on sensory nerve-endings in the extrinsic eye- muscles of the rabbit. ‘Atypical motor-endings’ of Retzius. Anat. Anz., Bd. 15.

An the occurrence of a n intracranial ganglion upon the oculornotor nerve in Scyllium canicula, with a suggestion as to its bearing upon the question of the segmental value of certain of the cranial nerves. Proc. of Royal Society; series B, June, vol. 88.

Observations on the sensual rOle of the proprioceptive nerve supply of the extrinsic ocular muscles.

1910 Receptors and afferents of the third, fourth, and sixth cranial nerves. Proc. of Royal Society, Series B, vol. 82.

THOMSEN, R. 1887 Ueher eigenthiiniliche aus veranderten Ganglienzellen her- vorgegangene Gebilde in den Stammen der Hirniierven des Menscheii. Virchow ’s Archiv, Bd. 109.

1912 On the presence of ganglion cells in tlie roots of the third, fourth, and sixth cranial nerves. Physiological Society Proceed- ing, July, 1912, Jour. of Physiol., vol. 43.

Jour. Physiol., vol. 10.

Johns Hopkins Hospital Bulletin, vol. 20. 1899

IYIcIioLLs, GEO. E. 1915

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