On the anatomy and physiology of the oblique muscles of the eye, in man and vertebrate animals / by John Struthers.

Date:
[1849]
Catalogue details

Licence: Public Domain Mark

Credit: On the anatomy and physiology of the oblique muscles of the eye, in man and vertebrate animals / by John Struthers. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    correct viewing of an object when the head is being moved, that the picture fall in all respects on the same part of the retina,—that a more or less direct movement of rotation on the antero-posterior axis is very necessary; and it may be added, that the nature of this movement—as it causes little or no change in the direction of the eye—together with the circumstances under which it takes place, are such as not to render its occurrence evident to an observer. The circumstances under which this movement would be required in those animals in which the eyes are placed in the side of the head, and look outwards, are different; as, in the simple movement of rais- ing or depressing the head, the latter moves more on an axis corres- ponding to that of the eyes, so as to render a more direct lateral ro- tatory motion necessary, in order to prevent the image from changing its place circularly on the retina. In these animals, it is doubtful if the eyes, which cannot be directed together to the same object, are moved simultaneously; but if so, the corresponding oblique muscles will be employed at the same time on opposite sides, whereas, in the circumstances explained by Hunter, the superior oblique of the one side would be in action along with the inferior of the other. These, however, are so far only theoretical considerations, and do not affect the conclusion to which comparative anatomy points, that the oblique muscles—whatever minor differences may obtain as to their arrangement in different vertebrate animals—are, in all, not only capable of performing this movement in opposite directions, but are evidently intended for doing so. It would thus appear, that, while comparative anatomy is irrecon- cilable with all the other theories above alluded to, it affords strong confirmation of the view that the oblique muscles are specially pro- vided for turning the eye, more or less directly, on its antero-posterior axis. MURRAY ANT) GIBB, PRINTERS, EDINBURGH.