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Anatomy of the orbit
Dr. Noura El Tahawy
Assist. Professor Of Anatomy
Embryology& Molecular Cell Biology
Faculty of Medicine, Port Said University,
Specific objectives of orbit
1. List the contents of the orbit.
2. Mention intrinsic muscles of the eyeball.
3. Describe levator palpebrae superiosis & The extraocular
muscles (origin –insertion-action & nerve supply)
4. Describe sensory& motor nerves in the orbit.
5. Describe blood vessels in the orbit.
6. Describe ciliary ganglion.
7. List structures passing through the optic canal &the
Orbital Plate of Frontal BoneLesser Wing of The Sphenoid
Roof of the orbit
The Frontal Process of Maxilla
The Lacrimal Bone
Part of Body of The Sphenoid
Medial wall of orbit
Orbital Surface of Maxilla
The Floor of the orbit
Special Features of The Bony Orbit
Superior Orbital Fissure
Inferior Orbital Fissure
1. Supraorbital notch
Forehead Supraorbital vessels & n.
2. Optic canal Middle cranial
CN. II, Ophthalmic a.
3. Sup. orbital fissure Middle cranial fossa CN. III, IV, V1, VI
4. Inf. orbital fissure Infratemporal fossa Infraorbital n. & vessels,
5. Posterior & anterior
Ethmoidal air cells Post & ant ethmoidal n.
6. Zygomatic canal Zygomaticofacial &
Zygomaticotemporal n. &
7. Bony nasolacrimal
8. Infraorbital groove
Infraorbital n. & vessels
A. External White Fibrous Coat
■ Consists of the sclera and the cornea.
■ Is a tough white fibrous coat enveloping the posterior five-sixths of the eye.
■ Is a transparent structure forming the anterior one-sixth of the external coat.
■ Is responsible for the refraction of light entering the eye.
B. Middle Vascular Pigmented Coat
■ Consists of the choroid, ciliary body, and iris.
■ Consists of an outer pigmented (dark brown) layer and an inner highly vascular layer, which invests
the posterior five-sixths of the eyeball.
■ Nourishes the retina and darkens the eye.
2. Ciliary Body
■ Is a thickened portion of the vascular coat between the choroid and the iris and consists of the
ciliary ring, ciliary processes, and ciliary muscle.
The ciliary muscle consists of smooth muscle
innervated by parasympathetic fi bers derived from oculomotor.
■ 1. Is a thin, contractile, circular, pigmented diaphragm with a central aperture, the pupil.
■ 2. Contains circular muscle fibers (sphincter pupillae), which are innervated by parasympathetic
fibers, and radial fibers (dilator pupillae), which are innervated by sympathetic fibers
1. The conjunctiva is the delicate mucous membrane lining the inner surface of the lids from which it
is reflected over the anterior part of the sclera to the cornea. Over the lids it is thick and highly
vascular, but over the sclera it is much thinner and over the cornea it is reduced to a single layer
2. of epithelium. The line of reflection from the lid to the sclera is known as the conjunctival fornix;
the superior fornix receives the openings of the lacrimal glands.
3. Movements of the eyelids are brought about by the contraction of the orbicularis oculi and levator
palpebrae superioris muscles. The width of the palpebral fissure at any one time depends on the
tone of these muscles and the degree of protrusion of the eyeball.
C) The inner neural coat
• The retina is formed by an outer pigmented and an inner nervous layer
• Posteriorly the nerve fibres on its surface collect to form the optic nerve.
• its posterior pole there is a pale yellowish area, the macula lutea, the site of
• central vision, and just medial to this is the pale optic disc formed by the
• passage of nerve fibres through the retina, corresponding to the ‘blind spot’.
• The central artery of the retina emerges from the disc and then divides
• into upper and lower branches; each of these in turn divides into a nasal
• and temporal branch.
• The layer of ganglion cells, whose axons form the superifical layer of optic nerve fibres
Nerves of the Orbit
▪ Sensory nerves
Optic nerve for vision
ophthalmic division of trigeminal (CV) nerve for
▪ Motor nerves
(The maxillary nerve passes through the inferior orbital fissure,
enters into the groove in floor of the orbit, continues as infraorbital
nerve, exits through infraorbital foramen and supplies the skin of
the face. Does not supply orbital contents)
▪ Pierces the sclera at a point medial to the
posterior pole of the eyeball.
▪ Runs backward& laterally within the cone of
the recti muscles
▪ Enters through optic canal
▪ Accompanied by opthalmic artery that lies
▪ Surrounded by meninges & the subarachnoid
space containing CSF
General sensory: Ophthalmic
division of trigeminal nerve
Remove the orbital plate of the frontal bones and the frontal bone above the superior orbital
margin. Beneath the periorbita or periosteum lining the orbit, locate the frontal nerve, one of
the three branches of the ophthalmic divisionof trigeminal nerve. Frontal nerve splits into
supraorbital and supratrochlear nerves to supply the skin of the forehead.
Match to the diagram
1. Orbital plate of
2. Frontal n.
3. Supraorbital n
4. .Supratrochlear n.
Indicate the nerve supply to each.
Sensory nerves are branches of the
ophthalmic division of the trigeminal-
III IV VI
Short ciliary nn.
Frontal n. (cut)
Long ciliary nn.
Motor nerves are branches of cranial nerves
III, IV, and VI
Vessels of the Orbit
▪ Arterial supply: Ophthalmic artery,
branch of internal carotid artery
Venous drainage: Superior & inferior
ophthalmic veins, drain into the
Veins of the Orbit
Superior & inferior
▪ Drain the orbital
▪ Pass through the
▪ Drain into the
▪ Communicates in
front with facial
through the inferior
orbital fissure with
There are NO lymph vessels
or lymph nodes in the
■ Lies in the upper lateral angle of the orbit . Supplied by parasympathetic
fibers from facial nerve.
■ Is drained by 12 lacrimal ducts, which open into the superior conjunctival
B. Lacrimal Canaliculi
■ Are two curved canals that begin as a lacrimal punctum (or pore) in the
margin of the upper& lower eyelid and open into the lacrimal sac.
C. Lacrimal Sac
■ Lies in the lacrimal groove at anterior inferior angle of medial wall of the
orbit . It drains into nasolacrimal duct, which opens into the inferior
meatus of the nasal cavity.
■ Are produced by the lacrimal gland.
■ Pass through excretory ductules into the superior conjunctival fornix.
■ Are spread evenly over the eyeball by blinking movements
■ Enter the lacrimal canaliculi through their lacrimal puncta (which is on the
summit of the lacrimal papilla) then draining into the lacrimal sac,
nasolacrimal duct, and finally, the inferior nasal meatus in the nasal cavity.