The orbit is a bony cavity quadrilateral pyramidal in shape.
It has four walls, seven bones contributed for its formation :(Maxilla,
The eyes seated in a hollow cone shaped cavity of the skull
Palatine, Zygomatic, Sphenoid, Frontal, Ethmoid and Lacrimal )
named orbit.
The movments of the eye are regulated by six
muscles.Fatty tissues in the orbit give it flexibility to The openings and structures that pass through them:
function. The optic canal(in the lesser wing of sphenoid bone):
The adnexal structres like eyebrows, eyelashes, eyelids, • Optic nerve with its sleeve of meninges.
protect eyes from foeeign elements and injuries.located in • Extension of subarachnoid space.
a space called the Orbit. • Ophthalmic artery ( branch of ICA) with its surrounding sympathetic plexus.
The superior orbital fissure:
• lacrimal nerve.
• Frontal nerve.
Structure of the Eyeball: • Trochlear nerve
• A slightly irregular hollow sphere with anterior • Upper and lower division of the 3rd cranial nerve .
and posterior poles • Nasociliary nerve
• The wall is composed of three tunics – • 6th cranial nerve
fibrous, vascular, and sensory • superior ophthalmic vein that empty in the cavernous sinus.
• The internal cavity is fluid filled with humors – The inferior orbital fissure:
aqueous and vitreous Eyeball The orbit • Maxillary nerve which immediately change its name to Infraorbital nerve.
• The lens separates the internal cavity into • Zygomatic nerve.
anterior and posterior segments • Branches of Pterygo-palatine ganglion.
• Fascial sheath of the eyeball ( Tendon's • Inferior ophthalmic vein that empty in the pterygoid venous plexus.
capsule ) : a thin membrane that envelops the
eyeball and separates it from the orbital fat.
🔸
Relation to the bony orbit:
Superior relation:
🔸 The roof
• Frontal air sinus
• Occasionally ethmoidal air cells
🔷
Lacrimal Apparatus: consist of Lacrimal glands and lacrimal passage
🔹 The lacrimal gland : 2 main groups • Orbital plate of the frontal bone. • Frontal lobe of cerebral hemisphere and its covering
Lacrimal gland proper (consists of two parts orbital and
palpebral ) its supplied by lacrimal branch of ophthalmic art& drained 🔸
• Lesser wing of the sphenoid bone.
The Lateral Wall
• Anteriorly by orbital surface of zygomatic bone.
🔸
meninges.
Inferior relation:
• Maxillary air sinus.
by lacrimal vein which joined the superior ophthalmic vein.
Nerve supply: sensory by the lacrimal branch of ophthalmic division
secreto motor by the parasympathetic fiber 7th cranial nerve. 🔸
• Posteriorly by the greater wing of sphenoid bone .
The floor:
Orbital process of Palatine bone.
• Infraorbital nerve and blood vessels in the Infraorbital
🔸
canal.
Lateral relation:
vasomotor by the sympathetic fibers ( post ganglionic cervical
ganglia) Lacrimal Apparatus Orbital surface of Maxillary bone. • Temporalis muscle anteriorly.
Lymphatic drainage: preauricular lymph node
•The accessory lacrimal glands( Krause's and Wolf ring glands) 🔸
Zygomatic bone.
The medial Wall:
• Sphenoid body.
• Temporal lobe of cerebral hemisphere and its meninges in
🔸
the middle cranial fossa.
Medial relation:
•Tears
– Contain mucus, antibodies, and lysozyme • Orbital plate of Ethmoid bone • Nasal cavity.
– Enter the eye via superolateral excretory ducts • Frontal process of the Maxilla. • Ethmoidal sinus.
– Exit the eye medially via the lacrimal punctum • Lacrimal bone. • Sphenoid sinus.
– Drain into the nasolacrimal duct
Orbital contents:
🔸
🔸 1. Eyeball and its Adnexa
🔷 The eye brow:
Coarse hairs that overlie the supraorbital
🔸 2. Orbital fat
3. Fascia:
a. Periosteum ( periorbita)
margins b. Septum orbitale
🔸
•Orbicularis muscle – depresses the eyebrows c. Tenon's capsule
•Corrugator muscles – move the eyebrows 4. Blood vessels :-
medially 1. Ophthalmic artery : it originated from internal carotid artery
These muscles innervated by the seventh Its branches:
cranial nerve. •1. Central retinal artery.
•2. Lacrimal art. ( it gives the lateral palpebral art.)
🔷 The Lids:
The eyelid is a thin fold of skin that covers and protects the eye. It divided by a horizontal furrow( sulcus) in to
•3. Muscular branches.
•4. Posterior ciliary arteries ( Short posterior ciliary art. , Long posterior ciliary art.
•5. Medial palpebral art.|
an orbital & tarsal part.
When the eye is opened the upper eyelid cover 1/6th of the cornea& the lower one just touch the limbus.
The margins of the upper and lower lids meet at the medial and lateral angles called canthus.
🔸
2. Ophthalmic veins: Superior and inferior.
5. nerves:
1. The sensory:
They bound an elliptical space “ the palpebral fissure”.
-Ophthalmic division of the trigeminal nerve.
The space at the medial canthus is called “Lacus Lacrimalis”. At the Lacus Lacrimalis there is a fold of
its branches:
conjunctiva called (Plica semilunaris” ، lateral to it is the “Lacrimal Caruncle). - Frontal ( which gives supraorbital and supratrochlear nerves) and Lacrimal ( lacrimal
Along the plane of the plica, there is an elevation in either lid, “ The Lacrimal Papilla” at the top of which is “The gland)
Lacrimal Punctum”. The free border of the lid carry the eye-lashes. - Nasociliary( witch gives sensory root of ciliary ganglion and long ciliary nerves).
The margin of the lid: 2. Motor innervations: 3rd , 4th , 6th cranial nerve.
• 2 mm thick.
• Has an anterior rounded border and posterior sharp border.
• Just anterior to the posterior border is the orifices of the tarsal glands, between these and the eyelashes is the
grey line. Adnexa anatomy of the eye
• The punctum and the lacrimal canaliculus in the medial 1/6th
•The eye lashes anteriorly and the orifices of the Meibomian glands posteriorly in the lateral 5/6th .
• A slightly irregular hollow sphere with anterior and posterior
poles
• The wall is composed of three tunics – fibrous, vascular, and
sensory
• The internal cavity is fluid filled with humors – aqueous and
vitreous
• The lens separates the internal cavity into anterior and
posterior segments
• Fascial sheath of the eyeball ( Tendon's capsule ) : a thin
Structure of the lids: membrane that envelops the eyeball and separates it from
1. The skin. the orbital fat.
🔶 The glands of the eyelids:
1. Meibomian glands: are modified sebaceous glands, embedded in the tarsal
2. Subcutaneous areolar connective tissue
3. Striated muscle: orbicularis oculi ( orbital, palpebral and lacrimal
portions)& levator palpebrae superioris ( upper eyelid)
plate, arranged vertically. 4. Sub muscular areolar connective tissue
2. Zeiss glands: sebaceous glands, open into the follicles of eyelashes. 5. Fibrous layer( the central tarsal plate& the peripheral orbital
3. Glands of Moll: modified sweat glands. septum)
🔶
4. Accessory lacrimal glands of Wolf ring. 6. Non striated muscle (muscle of Muller or tarsal muscle)
🔸 Blood supply:
Arterial: - Terminal branch of ophthalmic art.(medial palpebral and lateral
7. Palpebral conjunctiva( marginal , tarsal and orbital)
🔶 Vascular Tunic (Uvea):
Has three parts: iris ,ciliary body and choroid.
palpebral )- Arterial arches: formed by anastomosis of branches of the medial
and lateral palpebral arteries, in upper eyelid 2 arches (upper tarsal and marginal 🔸 Iris
🔸
) in the lower lid only marginal arch.
Veins: post-tarsal plexus…….. To the ophthalmic vein pre-tarsal plexus……… to
• The colored part of the eye• Pupil – central opening of the iris– Regulates the amount of light entering the eye
during:
🔶Sensory Tunic:
🔶 🔸
facial and temporal veins. – Close vision and bright light
🔸 Nerve supply:
Motor: -7th cranial nerve to the orbicularis oculi muscle - 3rd cranial nerve to
– pupils constrict
– Distant vision and dim light
Retina:
• A delicate two-layered membrane
🔸
the LPS - sympathetic fiber to the Muller's muscle
Sensory:
Trigeminal nerve:
– pupils dilate
Microscopically:
1. The anterior endothelium.
• Pigmented layer – the outer layer that absorbs light and prevents its scattering
• Neural layer, which contains:
– Photoreceptors that transduce light energy
1. Ophthalmic division to the upper eyelid via supra-trochlear, supra-orbital, 2. The stroma – Bipolar cells and ganglion cells
lacrimal and infra-trochlear ) 3. Muscles (sphincter pupillae, dilator pupillae ) – Amacrine and horizontal cells
🔶
2. Maxillary division to the lower eyelid via the infra-orbital nerve. 4. pigmented epithelium ( anterior and posterior ) Microscopically the retina composed of:
Lymph drainage : lateral part to the pre-auricular LN& parotid LN and the Blood supply: 1. The pigment epithelium.
medial part to the sub- mandibular LN Arteries: Circulus arteriouses major ( 2 long posterior ciliary, 7 anterior ciliary arteries ) Circulus arteriouses minor. 2. Rods and cones.
🔶 Fibrous Tunic:
• Forms the outermost coat of the eye and is composed sclera and cornea which
Veins: 4 vortex veins
Nerve supply of the iris:
3. External Limiting membrane.
4. Outer nuclear.
-Motor : short ciliary nerves which contain: 5. Outer plexiform.
🔸
meet at the limbus : 1. Parasympathetic fiber to Sphincter pupillae( via the third cranial nerve) 6. Inner nuclear.
Transparent membrane that: opaque Sclera (posterior): 2. Sympathetic fiber to the dilator pupillaeSensory: 7. Inner plexiform.
– Lines the eyelids as the palpebral conjunctiva ( marginal ,tarsal
🔸
Outer surface is in contact with the tenon’s capsule and bulbar conjunctiva, while on 2 long ciliary nerves. 8. Ganglionic cell.
&orbital ) 9. Nerve fiber
inner aspect is separated from the choroid by the supra-choriodal space. Ciliary Body:
– Covers the whites of the eyes as the bulbar conjunctiva ( It has apertures at three planes:- 10. Internal limiting membrane.
• A thickened ring of tissue surrounding the lens
scleral and limbal parts) – The posterior apertures: for Posterior – Ciliary vessels. • Composed of smooth muscle bundles (ciliary muscles)
– Fornix : is the junction of bulbar to palpebral conjunctiva.
– Plica semilunaris
Conjunctiva – The middle apertures: for vortex veins. • Anchors the suspensory ligament that holds the lens in place The important regions in the retina:-
– The anterior apertures: for Anterior ciliary vessels.– Consist of: • Extends from ora serrata posteriorly to scleral spur anteriorly. * The macula.The fovea centralis.
Structure of conjunctiva: 2 layers – Episclera – Stroma– Lamina fusca– Endothelial layer The foveola.* The optic disc.
1. The epithelium. Structure of the Eyeball • It is a triangular on cross section, the anterior surface is ridged and is called pars plicata, the posterior surface is
🔸
• Sclera – protects the eye and anchors extrinsic muscles smooth and is called the pars plana. Blood Supply to the Retina
2. The sub mucosal lamina properia( superficial lymphoid layer & Arteries:
Clear cornea (anterior): layers of cornea: Composed of:
deep fibroid layer The retina receives it blood supply from two sources
1. Epithelium ( 5-6 layers) • Ciliary muscles: consist of 3 parts:
2. Bowman's layer ( easily destroyed never regenerated). 1. longitudinal The outer laminae receives its blood from the choroid( Choriocapillaries)
by fatema okoff 3. Stroma (90% of corneal thickness) 2. oblique The inner laminae are served by the central retinal artery vein: central retinal vein it
4. Descemet”s membrane 3. circular end in the cavernous sinus .
5. Endothelium ( single layer) It is a vascular and its nutrition is obtained by diffusion • Ciliary processes ( 70-80) The posterior segment is filled with a clear gel called vitreous humor that:
from ( limbal capillaries, aqueous humour and tear film ( oxygen ) • Epithelium: outer pigmented and inner non pigmented • Transmits light ( refractive medium)
– Nerve supply: Blood supply: • - Supports the posterior surface of the lens
2 long ciliary nerves of the nasociliary branch of 5th cranial nerve. Arteries: circular arteriouses major and arteries forming it. • - Holds the neural retina firmly against the pigmented layer
– Corneal refractive power is 42 dioptres Veins: 4 vortex veins and anterior ciliary veins( carry blood from ciliary muscle) • Occupies four-fifth of the eyeball.
Nerve supply: • Maintain the form of the eye. Refractive media of the Eye.. Consists of the cornea,
🔸The Crystalline Lens..
Motor: parasympathetic fiber to the ciliary muscle ( via the 3rd cranial nerve) the aqueous humor, the lens, and the vitreous body.
Sensory:
2 long ciliary nerves.
🔸 Choroid :
❖Transparent, biconvex structure situated behind the iris and pupil and in front of
the vitreous body.
– A dark brown membrane that forms the posterior portion of the uveaSupplies blood to all eye tunics Thin, ❖ Made up of:
vascular membrane, extending from optic disc to ora serrate. Histological structure: 1) Elastic capsule.
It has 5 layers : 2) Sub capsular epithelium(confined to the anterior surface)
1. Supra choroidal lamina. 3) lens fibers: superficial fiber:
2. Vascular Layer : the new soft lens fibers( in the cortex)
- outer large vessels. - middle small vessels. - inner Chorio capillaries. deep fiber: the older hard lens fibers( form the nucleus)
3.Bruch's membrane.
Blood supply:
Arteries: posterior part: short posterior ciliary art. anterior part: circular arteriouses major
Veins: 4 vortex veins
N.B. it is insensitive as there is no pain nerve ending
The extra Ocular muscles:
Comprise:
🔸
-Four rectus and two oblique and Levator Palpebral Superiori
Origin of rectus muscles from “The common tendenous ring” “Annulus of Zinn”.
And inserted in the sclera anterior to the equator at a different distance from the limbus( MR:5.5 mm, IR: 6.5 mm, LR: 6.9
🔸
mm, SR:7.7 mm)
The superior oblique:-
- Origin: The same as rectus Insertion: at the sclera behind the equator in the upper posterio- lateral part. The inferior
oblique
Origin: From orbital plate of the maxilla Lateral to Lacrimal Fossa.
Insertion:- at the sclera behind the equator in the lower posterio- lateral part of sclera.
Nerve supply:
oculomotor 3rd cranial nerve:
🔸
Superior division: SR, inferior division : MR, IR, IO.Trochlear 4th cranial nerve: SO.Abduscent 6th cranial nerve: LR.
The Levator Palpebral Superioris:-
Origin: From under surface of the lesser wing of the sphenoid and in front of optic foramen.
Insertion:-
1. Skin of the upper lid.
2. The front and lower part of tarsal plate.
3. Conjunctiva of superior fornix.
4. The two horns get attached to the mid point of the medial and lateral palpebral ligaments. .
It has four walls, seven bones contributed for its formation :(Maxilla,
The eyes seated in a hollow cone shaped cavity of the skull
Palatine, Zygomatic, Sphenoid, Frontal, Ethmoid and Lacrimal )
named orbit.
The movments of the eye are regulated by six
muscles.Fatty tissues in the orbit give it flexibility to The openings and structures that pass through them:
function. The optic canal(in the lesser wing of sphenoid bone):
The adnexal structres like eyebrows, eyelashes, eyelids, • Optic nerve with its sleeve of meninges.
protect eyes from foeeign elements and injuries.located in • Extension of subarachnoid space.
a space called the Orbit. • Ophthalmic artery ( branch of ICA) with its surrounding sympathetic plexus.
The superior orbital fissure:
• lacrimal nerve.
• Frontal nerve.
Structure of the Eyeball: • Trochlear nerve
• A slightly irregular hollow sphere with anterior • Upper and lower division of the 3rd cranial nerve .
and posterior poles • Nasociliary nerve
• The wall is composed of three tunics – • 6th cranial nerve
fibrous, vascular, and sensory • superior ophthalmic vein that empty in the cavernous sinus.
• The internal cavity is fluid filled with humors – The inferior orbital fissure:
aqueous and vitreous Eyeball The orbit • Maxillary nerve which immediately change its name to Infraorbital nerve.
• The lens separates the internal cavity into • Zygomatic nerve.
anterior and posterior segments • Branches of Pterygo-palatine ganglion.
• Fascial sheath of the eyeball ( Tendon's • Inferior ophthalmic vein that empty in the pterygoid venous plexus.
capsule ) : a thin membrane that envelops the
eyeball and separates it from the orbital fat.
🔸
Relation to the bony orbit:
Superior relation:
🔸 The roof
• Frontal air sinus
• Occasionally ethmoidal air cells
🔷
Lacrimal Apparatus: consist of Lacrimal glands and lacrimal passage
🔹 The lacrimal gland : 2 main groups • Orbital plate of the frontal bone. • Frontal lobe of cerebral hemisphere and its covering
Lacrimal gland proper (consists of two parts orbital and
palpebral ) its supplied by lacrimal branch of ophthalmic art& drained 🔸
• Lesser wing of the sphenoid bone.
The Lateral Wall
• Anteriorly by orbital surface of zygomatic bone.
🔸
meninges.
Inferior relation:
• Maxillary air sinus.
by lacrimal vein which joined the superior ophthalmic vein.
Nerve supply: sensory by the lacrimal branch of ophthalmic division
secreto motor by the parasympathetic fiber 7th cranial nerve. 🔸
• Posteriorly by the greater wing of sphenoid bone .
The floor:
Orbital process of Palatine bone.
• Infraorbital nerve and blood vessels in the Infraorbital
🔸
canal.
Lateral relation:
vasomotor by the sympathetic fibers ( post ganglionic cervical
ganglia) Lacrimal Apparatus Orbital surface of Maxillary bone. • Temporalis muscle anteriorly.
Lymphatic drainage: preauricular lymph node
•The accessory lacrimal glands( Krause's and Wolf ring glands) 🔸
Zygomatic bone.
The medial Wall:
• Sphenoid body.
• Temporal lobe of cerebral hemisphere and its meninges in
🔸
the middle cranial fossa.
Medial relation:
•Tears
– Contain mucus, antibodies, and lysozyme • Orbital plate of Ethmoid bone • Nasal cavity.
– Enter the eye via superolateral excretory ducts • Frontal process of the Maxilla. • Ethmoidal sinus.
– Exit the eye medially via the lacrimal punctum • Lacrimal bone. • Sphenoid sinus.
– Drain into the nasolacrimal duct
Orbital contents:
🔸
🔸 1. Eyeball and its Adnexa
🔷 The eye brow:
Coarse hairs that overlie the supraorbital
🔸 2. Orbital fat
3. Fascia:
a. Periosteum ( periorbita)
margins b. Septum orbitale
🔸
•Orbicularis muscle – depresses the eyebrows c. Tenon's capsule
•Corrugator muscles – move the eyebrows 4. Blood vessels :-
medially 1. Ophthalmic artery : it originated from internal carotid artery
These muscles innervated by the seventh Its branches:
cranial nerve. •1. Central retinal artery.
•2. Lacrimal art. ( it gives the lateral palpebral art.)
🔷 The Lids:
The eyelid is a thin fold of skin that covers and protects the eye. It divided by a horizontal furrow( sulcus) in to
•3. Muscular branches.
•4. Posterior ciliary arteries ( Short posterior ciliary art. , Long posterior ciliary art.
•5. Medial palpebral art.|
an orbital & tarsal part.
When the eye is opened the upper eyelid cover 1/6th of the cornea& the lower one just touch the limbus.
The margins of the upper and lower lids meet at the medial and lateral angles called canthus.
🔸
2. Ophthalmic veins: Superior and inferior.
5. nerves:
1. The sensory:
They bound an elliptical space “ the palpebral fissure”.
-Ophthalmic division of the trigeminal nerve.
The space at the medial canthus is called “Lacus Lacrimalis”. At the Lacus Lacrimalis there is a fold of
its branches:
conjunctiva called (Plica semilunaris” ، lateral to it is the “Lacrimal Caruncle). - Frontal ( which gives supraorbital and supratrochlear nerves) and Lacrimal ( lacrimal
Along the plane of the plica, there is an elevation in either lid, “ The Lacrimal Papilla” at the top of which is “The gland)
Lacrimal Punctum”. The free border of the lid carry the eye-lashes. - Nasociliary( witch gives sensory root of ciliary ganglion and long ciliary nerves).
The margin of the lid: 2. Motor innervations: 3rd , 4th , 6th cranial nerve.
• 2 mm thick.
• Has an anterior rounded border and posterior sharp border.
• Just anterior to the posterior border is the orifices of the tarsal glands, between these and the eyelashes is the
grey line. Adnexa anatomy of the eye
• The punctum and the lacrimal canaliculus in the medial 1/6th
•The eye lashes anteriorly and the orifices of the Meibomian glands posteriorly in the lateral 5/6th .
• A slightly irregular hollow sphere with anterior and posterior
poles
• The wall is composed of three tunics – fibrous, vascular, and
sensory
• The internal cavity is fluid filled with humors – aqueous and
vitreous
• The lens separates the internal cavity into anterior and
posterior segments
• Fascial sheath of the eyeball ( Tendon's capsule ) : a thin
Structure of the lids: membrane that envelops the eyeball and separates it from
1. The skin. the orbital fat.
🔶 The glands of the eyelids:
1. Meibomian glands: are modified sebaceous glands, embedded in the tarsal
2. Subcutaneous areolar connective tissue
3. Striated muscle: orbicularis oculi ( orbital, palpebral and lacrimal
portions)& levator palpebrae superioris ( upper eyelid)
plate, arranged vertically. 4. Sub muscular areolar connective tissue
2. Zeiss glands: sebaceous glands, open into the follicles of eyelashes. 5. Fibrous layer( the central tarsal plate& the peripheral orbital
3. Glands of Moll: modified sweat glands. septum)
🔶
4. Accessory lacrimal glands of Wolf ring. 6. Non striated muscle (muscle of Muller or tarsal muscle)
🔸 Blood supply:
Arterial: - Terminal branch of ophthalmic art.(medial palpebral and lateral
7. Palpebral conjunctiva( marginal , tarsal and orbital)
🔶 Vascular Tunic (Uvea):
Has three parts: iris ,ciliary body and choroid.
palpebral )- Arterial arches: formed by anastomosis of branches of the medial
and lateral palpebral arteries, in upper eyelid 2 arches (upper tarsal and marginal 🔸 Iris
🔸
) in the lower lid only marginal arch.
Veins: post-tarsal plexus…….. To the ophthalmic vein pre-tarsal plexus……… to
• The colored part of the eye• Pupil – central opening of the iris– Regulates the amount of light entering the eye
during:
🔶Sensory Tunic:
🔶 🔸
facial and temporal veins. – Close vision and bright light
🔸 Nerve supply:
Motor: -7th cranial nerve to the orbicularis oculi muscle - 3rd cranial nerve to
– pupils constrict
– Distant vision and dim light
Retina:
• A delicate two-layered membrane
🔸
the LPS - sympathetic fiber to the Muller's muscle
Sensory:
Trigeminal nerve:
– pupils dilate
Microscopically:
1. The anterior endothelium.
• Pigmented layer – the outer layer that absorbs light and prevents its scattering
• Neural layer, which contains:
– Photoreceptors that transduce light energy
1. Ophthalmic division to the upper eyelid via supra-trochlear, supra-orbital, 2. The stroma – Bipolar cells and ganglion cells
lacrimal and infra-trochlear ) 3. Muscles (sphincter pupillae, dilator pupillae ) – Amacrine and horizontal cells
🔶
2. Maxillary division to the lower eyelid via the infra-orbital nerve. 4. pigmented epithelium ( anterior and posterior ) Microscopically the retina composed of:
Lymph drainage : lateral part to the pre-auricular LN& parotid LN and the Blood supply: 1. The pigment epithelium.
medial part to the sub- mandibular LN Arteries: Circulus arteriouses major ( 2 long posterior ciliary, 7 anterior ciliary arteries ) Circulus arteriouses minor. 2. Rods and cones.
🔶 Fibrous Tunic:
• Forms the outermost coat of the eye and is composed sclera and cornea which
Veins: 4 vortex veins
Nerve supply of the iris:
3. External Limiting membrane.
4. Outer nuclear.
-Motor : short ciliary nerves which contain: 5. Outer plexiform.
🔸
meet at the limbus : 1. Parasympathetic fiber to Sphincter pupillae( via the third cranial nerve) 6. Inner nuclear.
Transparent membrane that: opaque Sclera (posterior): 2. Sympathetic fiber to the dilator pupillaeSensory: 7. Inner plexiform.
– Lines the eyelids as the palpebral conjunctiva ( marginal ,tarsal
🔸
Outer surface is in contact with the tenon’s capsule and bulbar conjunctiva, while on 2 long ciliary nerves. 8. Ganglionic cell.
&orbital ) 9. Nerve fiber
inner aspect is separated from the choroid by the supra-choriodal space. Ciliary Body:
– Covers the whites of the eyes as the bulbar conjunctiva ( It has apertures at three planes:- 10. Internal limiting membrane.
• A thickened ring of tissue surrounding the lens
scleral and limbal parts) – The posterior apertures: for Posterior – Ciliary vessels. • Composed of smooth muscle bundles (ciliary muscles)
– Fornix : is the junction of bulbar to palpebral conjunctiva.
– Plica semilunaris
Conjunctiva – The middle apertures: for vortex veins. • Anchors the suspensory ligament that holds the lens in place The important regions in the retina:-
– The anterior apertures: for Anterior ciliary vessels.– Consist of: • Extends from ora serrata posteriorly to scleral spur anteriorly. * The macula.The fovea centralis.
Structure of conjunctiva: 2 layers – Episclera – Stroma– Lamina fusca– Endothelial layer The foveola.* The optic disc.
1. The epithelium. Structure of the Eyeball • It is a triangular on cross section, the anterior surface is ridged and is called pars plicata, the posterior surface is
🔸
• Sclera – protects the eye and anchors extrinsic muscles smooth and is called the pars plana. Blood Supply to the Retina
2. The sub mucosal lamina properia( superficial lymphoid layer & Arteries:
Clear cornea (anterior): layers of cornea: Composed of:
deep fibroid layer The retina receives it blood supply from two sources
1. Epithelium ( 5-6 layers) • Ciliary muscles: consist of 3 parts:
2. Bowman's layer ( easily destroyed never regenerated). 1. longitudinal The outer laminae receives its blood from the choroid( Choriocapillaries)
by fatema okoff 3. Stroma (90% of corneal thickness) 2. oblique The inner laminae are served by the central retinal artery vein: central retinal vein it
4. Descemet”s membrane 3. circular end in the cavernous sinus .
5. Endothelium ( single layer) It is a vascular and its nutrition is obtained by diffusion • Ciliary processes ( 70-80) The posterior segment is filled with a clear gel called vitreous humor that:
from ( limbal capillaries, aqueous humour and tear film ( oxygen ) • Epithelium: outer pigmented and inner non pigmented • Transmits light ( refractive medium)
– Nerve supply: Blood supply: • - Supports the posterior surface of the lens
2 long ciliary nerves of the nasociliary branch of 5th cranial nerve. Arteries: circular arteriouses major and arteries forming it. • - Holds the neural retina firmly against the pigmented layer
– Corneal refractive power is 42 dioptres Veins: 4 vortex veins and anterior ciliary veins( carry blood from ciliary muscle) • Occupies four-fifth of the eyeball.
Nerve supply: • Maintain the form of the eye. Refractive media of the Eye.. Consists of the cornea,
🔸The Crystalline Lens..
Motor: parasympathetic fiber to the ciliary muscle ( via the 3rd cranial nerve) the aqueous humor, the lens, and the vitreous body.
Sensory:
2 long ciliary nerves.
🔸 Choroid :
❖Transparent, biconvex structure situated behind the iris and pupil and in front of
the vitreous body.
– A dark brown membrane that forms the posterior portion of the uveaSupplies blood to all eye tunics Thin, ❖ Made up of:
vascular membrane, extending from optic disc to ora serrate. Histological structure: 1) Elastic capsule.
It has 5 layers : 2) Sub capsular epithelium(confined to the anterior surface)
1. Supra choroidal lamina. 3) lens fibers: superficial fiber:
2. Vascular Layer : the new soft lens fibers( in the cortex)
- outer large vessels. - middle small vessels. - inner Chorio capillaries. deep fiber: the older hard lens fibers( form the nucleus)
3.Bruch's membrane.
Blood supply:
Arteries: posterior part: short posterior ciliary art. anterior part: circular arteriouses major
Veins: 4 vortex veins
N.B. it is insensitive as there is no pain nerve ending
The extra Ocular muscles:
Comprise:
🔸
-Four rectus and two oblique and Levator Palpebral Superiori
Origin of rectus muscles from “The common tendenous ring” “Annulus of Zinn”.
And inserted in the sclera anterior to the equator at a different distance from the limbus( MR:5.5 mm, IR: 6.5 mm, LR: 6.9
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mm, SR:7.7 mm)
The superior oblique:-
- Origin: The same as rectus Insertion: at the sclera behind the equator in the upper posterio- lateral part. The inferior
oblique
Origin: From orbital plate of the maxilla Lateral to Lacrimal Fossa.
Insertion:- at the sclera behind the equator in the lower posterio- lateral part of sclera.
Nerve supply:
oculomotor 3rd cranial nerve:
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Superior division: SR, inferior division : MR, IR, IO.Trochlear 4th cranial nerve: SO.Abduscent 6th cranial nerve: LR.
The Levator Palpebral Superioris:-
Origin: From under surface of the lesser wing of the sphenoid and in front of optic foramen.
Insertion:-
1. Skin of the upper lid.
2. The front and lower part of tarsal plate.
3. Conjunctiva of superior fornix.
4. The two horns get attached to the mid point of the medial and lateral palpebral ligaments. .
