Substantia propria
From Wikipedia, the free encyclopedia
| Substantia propria | |
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| Vertical section of human cornea from near the margin. (Waldeyer.) Magnified. 1. Epithelium. 2. Anterior elastic lamina. 3. substantia propria. 4. Posterior elastic lamina. 5. Endothelium of the anterior chamber. a. Oblique fibers in the anterior layer of the substantia propria. b. Lamellæ the fibers of which are cut across, producing a dotted appearance. c. Corneal corpuscles appearing fusiform in section. d. Lamellæ the fibers of which are cut longitudinally. e. Transition to the sclera, with more distinct fibrillation, and surmounted by a thicker epithelium. f. Small blood vessels cut across near the margin of the cornea. |
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| Latin | s. propria corneae |
| Gray's | subject #225 1007 |
| Dorlands/Elsevier | s_27/12766936 |
The substantia propria (or stroma of cornea) is fibrous, tough, unyielding, and perfectly transparent.
It is composed of about sixty flattened lamellæ, superimposed one on another. These fibrils run at different angles between limbi. However, posterior lamellæ tend to interweave less than anterior lamellæ. The lamellae are produced by keratocytes, which occupy about 10% of the substantia propria.
These lamellæ are made up of bundles of modified connective tissue, the fibres of which are directly continuous with those of the sclera. More collagen fibres run in a temporal-nasal direction than run in the superior-inferior direction. This is often ignored by corneal transplant surgeons, leading to poor corneal mechanical strength in corneal transplant patients.
The fibres of each lamella are for the most part parallel with one another, but at right angles to those of adjacent lamellæ.
Fibres, however, frequently pass from one lamella to the next.
Keratoconus is a condition caused by disorganised lamellæ, leading to a bulbous cornea.
