The sclera is the tough white sheath that
forms the outer-layer of the ball.
It is also referred to by other terms, including the sclerotic
and the sclerotic
coat (both having exactly the same meaning as the sclera).
In all cases these names are due to the the extreme density and hardness
of the sclera (sclerotic layer). It is a firm fibrous membrane that maintains
the shape of the eye as an approximately globe shape. It is much thicker
towards the back/posterior aspect of the eye than towards the front/anterior
of the eye.
The white sclera continues around the eye; most of which is not visible
while the eyeball is located in its socket within the face/skull. The
main area of the eye that is not covered by the area is the front part
of the eye that is protected by the transparent cornea
instead.
The Structure of the Sclera
The sclera is composed of white fibrous tissue intermixed with fine elastic
fibers and corpuscles of flattened connective-tissue. These fibers are
grouped together in bundles.
Blood supply to the sclera is via small (but not very numerous) interlinking
capillaries.
The nerves connected to the sclera are from the ciliary
nerves.
For further detail we recommend Gray's
Anatomy - an excellent general text that is informative yet inexpensive. |
