Anatomical and physiological observations. Pt. I / by John Struthers.

  • Struthers, John, 1823-1899.
Date:
1854
Catalogue details

Licence: Public Domain Mark

Credit: Anatomical and physiological observations. Pt. I / by John Struthers. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    latter the superior lias tlie advantage of being fleshy beyond the pulley, which is tlien large and loose, so as not to confine the muscular fibres. The oblique muscles appear, also, to be more developed in most quadrupeds than in man, when compared with the straight muscles and with the size of the eye; but, on the other hand, in man the oblique muscles pass more round the eye, from which they would appear to gain an advantage, as regards turning the eye on its axis. Farther, the lesser development of the oblique muscles, compared with the recti, in mammals, than in the inferior classes, may perhaps be more correctly regarded as due to the increase of the recti in the former, in accordance with the greater frequency and extent of the movements of the eye, more especially in man, and also in other mammalia. USE OF THE OBLIQUE MUSCLES. These observations may be regarded as affording just grounds from which to draw conclusions as to the use of the oblique muscles. Whatever minor differences they may present, they are evidently the same muscles, and provided for the same pui- pose in all vertebrate animals, and no hypothesis can be enter- tained if it is incompatible with, or not supported by, compara- tive anatomy. It has been a common opinion that the oblique muscles ad- Vance the eye, and act as antagonists to the recti, so as also to steady the eye during the action of the latter. To this it has been objected, that they exist in animals where the eye cannot be retracted, and that they are not proportionally increased where a special retractor or suspensory muscle exists. To this it may be added, that they exist in man in whom retraction of the eye does not naturally occur as a voluntary movement (as is easily ascertained by experiment, the strongest voluntary effort to do so being fruitless), although, by the conjoint action of all the straight muscles, or of two opposite ones, such a move- ment would be produced; and in most mammals the course of the oblique muscles in the orbit is not sufficiently backwards to