The document describes the anatomy of the eye and its associated structures. It discusses the various parts that make up the eyeball itself including the cornea, iris, retina, vitreous body, crystalline lens and chambers. It also describes the extraocular muscles, eyelids, lacrimal apparatus and other accessory structures. The summary provides a high-level overview of the key components and their functions in 3 sentences or less.
3. The eye or organ of vision usually it comprises of;
The eyeball or globe of the eye (Bulbus oculi)
The optic nerve
Certain accessory organs
The accessory organs are;
Orbital fasciae and muscles
The eyelids and conjunctiva, and
The lacrimal apparatus
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4. The bony walls of the orbit have been described in
connection with the skull; the peri-orbita, a fibrous
membrane which encloses the eyeball together with
its muscles, vessels, and nerves may be appropriately
included in the account of the fasciae
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5. The eyelids, upper and lower are movable folds of skin
situated in front of the eyeball.
The upper lid more movable than the lower one, and
its free interval between the lids is termed the
palpebral fissure
The ends of the fissure are the
angles/comissures , and are
distinguished as medial or nasal,
and lateral or temporal
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6. The third eyelid is situated at the medial angle of the
eye.
It consists of a semi-lunar fold of the conjunctiva,
known as the membrana nictitans,
which covers and partly encloses a curved plate of
hyaline cartilage. Its marginal part is thin and usually
more or less pigmented.
The deep part is narrower and thicker and is
embedded in fat at the inner side of the eyeball
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7. The skin of the eyelids is thin and freely movable,
except near the free edge, where it is more firmly
attached.
The underlying subcutaneous tissue is composed of
fat.
The muscular layer consists chiefly of the elliptical
bundles of the orbicularis oculi, with which are
associated fibers of the supercilii in the upper lid and
the malaris in the lower lid.
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8. At the medial side
there is a fibrous band,
the palpebral ligament,
which is attached to
the lacrimal tubercle
and provides origin to
some fibres of the
orbicularis.
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9. At the medial commissure a bundle detached from the
orbicularis passes inward behind the lacrimal sac, and
is known as the pars lacrimalis (Horner's muscle)
At the lateral side the fibrous layer is thicker and
denser along the free edge of the lid, forming here the
tarsus.
The tarsus provides insertion to a layer of unstriped
muscle known as the tarsal muscle.
The tarsal glands (Glandulse tarsales) are partly
embedded in the deep face of the tarsus.
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10. The conjunctiva is the mucous membrane which lines
the lids as palpebral conjunctiva (C. palpebrarum),
and is reflected upon the anterior part of the eyeball as
bulbar conjunctiva (C. bulbi); the line of reflection is
termed the fornix conjunctiva.
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11. there is a rounded pigmented prominence known as
the lacrimal caruncle
about the size of a small pea, and is covered modified
skin, connected with that of the medial commissure,
from which project a number of hairs provided with
sebaceous glands.
slit-like opening, the pictum lacrimal, which is the
entrance to the lacrimal duct.
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12. It is composed of:
Lacrimal Gland
Which secretes lacrimal fluid
Excretory ducts of gland
The pimcta lacrimalia are the entrances to the two lacrimal
ducts.
Lacrimal ducts
Canaliculi
Lacrimal sac
Naso-lacrimal duct
Which receive fluid & convey it to nostrils
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13. The anterior margin bears stiff hairs termed the cilia
(eyelashes).
On the upper lid the cilia are long and numerous except
at its medial third, where they are very small or absent.
On the lower lid the cilia are often scarcely distinguish-
able from the ordinary hairs
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Cilia
14. Sensory Nerves
branches of the ophthalmic and maxillary
divisions of the trigeminus.
Motor Nerves
Orbicularis oculi, supercilii, and malaris come from
the facial nerve
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15. The straight muscles of the eyeball and the oblique
muscles in part are enclosed in fibrous sheaths
Superficial fascia (Thin)
Deep fascia
Fascia bulbi (cover the posterior part of eyeball)
Levator palpebrae superioris
Muscles of the eyeball are seven in number—four
straight, two oblique, and a retractor
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16. Obliquus dorsalis s. Superior (longest and narrowest of
the ocular muscles)
Obliquus ventralis s. Inferior (wide and much shorter
than the recti)
Retractor oculi (Surround the optic nerve)
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17. Rectus dorsalis
s. superior
Rectus ventralis
s. inferior
Rectus medialis
Rectus lateralis
They are all band-like
arise close together around the optic foramen
diverge as they pass forward to the eyeball.
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18. situated in the anterior part of the orbital cavity
protected in front by the eyelids and conjunctiva, and
in its middle by the complete orbital ring
related behind to the fascia bulbi, fat, and ocular
muscles.
form approximately a sphere
composed of the segments of
two spheres of different sizes
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19. forms the anterior fifth of the fibrous tunic
transparent
colorless
non-vascular
oval in outline
anterior surface is convex
central part is termed the vertex comeae.
posterior surface (Facies posterior) is concave
The margin (Limbus corneae) joins the sclera
cornea is thinnest at the vertex
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22. The retina or nervous tunic of the eyeball is a delicate
membrane which extends from the entrance of the
optic nerve to the margin of the pupil.
consists of three parts
large posterior part
• pars ciliaris retinae
• Pars iridica retinae
• optic papilla
(Papilla nervi optici)
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23. pigmented epithelium (Stratum pigmenti retinae)
arteria centralis retinae
anastomotic branches from the short ciliary arteries
veins accompany the arteries except in the capillary
plexuses; their walls consist merely of a layer of
endothelial cells, around which are a lymph-channel
and sheath.
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24. anterior chamber
posterior chamber
The chambers are filled by the aqueous humor
clear fluid which consists of about 98% of water, with a
little sodium chlorid and traces of albumin and
extractives.
It is carried off chiefly through the spaces in the
zonula ciliaris (suspensory ligament of the lens) into
the plexus venosus sclerae.
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26. vitreous body is a semifluid
transparent substance situated between the crystalline
lens and the retina
In front it presents a deep cavity, the fossa hyaloidea,
which fits the posterior surface of the lens
vitreous stroma
vitreous humor
The surface is covered by a condensation of the stroma
known as the hyaloid membrane
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27. crystalline lens is a biconvex
Equator of the lens is almost circular
Anterior surface is convex
Posterior surface is much more strongly curved than
the anterior
The central points of the surfaces are the anterior and
posterior poles and the line which connects them is
the axis of the lens
zonula ciliaris is suspensory ligament of the lens
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