Landmarks, medical and surgical / by Luther Holden ; assisted by James Shuter.

  • Luther Holden
Date:
1881
Catalogue details

Licence: Public Domain Mark

Credit: Landmarks, medical and surgical / by Luther Holden ; assisted by James Shuter. Source: Wellcome Collection.

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    14. Eyelids and eyes.—The opening between the eyelids varies in size in different persons ; hence more of the eyeball is seen in some than in others, and the eye appears larger. Although human eyes do vary a little in size, yet the actual difference is by no means so great as is generally supposed. The size of the fissure has much to do with the apparent size of the eye. Contrast the narrow fissure of the Chinese and Mongolian races, and the apparent smallness of their eyes with those of Europeans. As a rule the external angle of the lid is higher than the internal. When not exaggerated, it gives the face an arch and pleasing ex- pression. Evert the lids to see the Meibomian glands ; observe their perpendicular arrangement, in the substance of the tarsal cartilages. The free borders of the lids are not bevelled, as described by J. L. Petit and most anatomists, * so as to form with the globe of the closed eye a triangular canal for the flow of the tears.' On the contrary, it is easily seen that the lid margins, when closed, come into accurate contact. Their plane is not exactly horizontal, but slightly inclined upwards. Every time the eye is shut, the ball turns upwards and inwards, so that the cornea is completely covered by the upper lid. This may be well seen by raising the lid of a sleeping infant ; also in cases of low fever when the lid is not completely closed. This up-turning of the eye obviously clears the cornea, and protects it from the light. A careful examination of the motion of the lower lid in the act of shutting the eye proves that it is a double motion. The lid is not only slightly raised, but drawn inwards about of an inch. This second movement sweeps any particles of dust as well as moisture towards the inner canthus. 15. Puncta lachrymalia.—The puncta lachrymalia are distinctly visible at the inner angles of the lids. The lower punctum is larger and a little more external than the upper, so that they are not exactly opposite. The direction, too, of the puncta deserves notice. Their open mouths look a little backwards, ready to imbibe the tears. When their proper
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