Download Anterior ethmoidal nerve

ORBITAL CAVITY
A pyramidal space with a base, apex and four walls.
Boundaries and Walls:
Roof
Orbital plate of frontal b.
Lesser wing of sphenoid b.
•
1.
2.
3.
Floor
Orbital surface of maxilla
Zygomatic bone
Orbital process of palatine b.
•
1.
2.
3.
Medial wall
Lacrimal bone
Orbital plate of ethmoid b.
Body of sphenoid b.
•
1.
2.
Lateral wall
Zygomatic b.
Greater wing of sphenoid b.
Frontal
bone
Greater wing
of sphenoid
Ethmoid
bone
Maxillary
bone
Lacrimal bone
•
1.
2.
Some Features of The Orbit
•Lacrimal fossa (1)
•Lacrimal groove and crests (2)
•Trochlear fovea (3)
•Ant. and post. ethmoidal canals (4)
•Zygomatico-facial and Z-temporal canals
•Optic canal (5)
•Supraorbital foramen (6)
•Infraorbital groove, canal and foramen (7)
•Superior orbital fissure (8)
•Inferior orbital fissure (9)
(lodges the orbital part of the lacrimal gland)
(lodges the lacrimal sac)
(attachment of the trochlea)
(ant. and post. ethmoidal nerves and vessels)
(zygomaticofacial and z-temporal n. and v.)
(optic nerve, ophthalmic a. & meningeal sheath)
(supraorbital n. and v.)
(infraorbital n. and v.)
6
3
1
4
5
8
2
9
7
7
Communications of the Orbit
The orbital cavity communicates with the:
•Anterior cranial fossa via ant. and post. ethmoidal canals (1)
•Middle cranial fossa
via optic canal and the superior orbital fissure (2, 3)
•Infratemporal fossa
via inferior orbital fissure (4)
•Nasal cavity
via nasolacrimal canal (5)
1
2
3
5
4
Contents of the Orbital Cavity
•Orbital fat
•Eyeball
•Muscles
•Vessels
•Nerves
•Ciliary ganglion
•Lacrimal gland
Muscles of the Orbit
Levator palpebrae suprioris
Extrinsic muscles of the eye
4 Recti muscles
•Superior rectus
•Inferior rectus
•Medial rectus
•Lateral rectus
2 Oblique muscle
•Superior oblique
•Inferior oblique
Intrinsic muscles of the eye
•Dilator pupillae
•Constrictor pupillae
•Ciliary muscle
Levator palpebrae superioris m.
O:
I:
A:
N:
roof of the orbit in front of the optic canal
superficial lamella:
front of superior tarsus & skin of upper eyelid
deep lamella:
upper border of superior tarsus & superior fornix of conjunctiva
elevation of upper eyelid and sup fornix of conjunctiva
sup division of oculomotor n.
Levator
palp sup
Lev
Palp
Sup
Insertion of
lev palp sup
Superior
tarsus
Recti Muscles: (sup, inf, med, lat)
O: common tendinous ring, according to their position (the lateral rectus m. arises by 2 heads)
I: into the sclera, at varying distances from the limbus (corneo-scleral junction)
A: directing the cornea vertically or horizontally according the their name
(sup. and inf. recti produce some medial deviation in addition to the vertical movement)
N.S.: -sup rectus
(sup division of oculomotor)
-inf & med rectus
(inf division of oculomotor)
-lat rectus
(abducent)
Superior rectus
Levator palp
superioris
Lateral
rectus
Superior oblique
Med rectus
Inf. oblique
Levator palp
superioris
Lateral rectus
Superior oblique
Superior oblique
O: junction of the roof with medial surface of the orbit (in front of the common tendinous ring)
I: its tendon passes through the trochlea, inserted into the sclera behind the equator of eyeball
A: directs the cornea downwards and laterally
N.S.: trochlear n.
Inferior oblique
O: anterior part of the floor of the orbit
I: runs laterally and upwards, inserted into the sclera behind the equator of the eyeball
A: directs the cornea upwards and laterally
N. S. : inferior division of oculomotor n.
Intrinsic Muscles of the Eye
•Sphincter pupillae (constrictor of the pupil)
•Ciliary muscle (accommodation to near vision)
Both muscles are supplied by parasympathetic fibers (through the short ciliary nerves)
•Dilator pupillae (dilator of the pupil)
Supplied by sympathetic fibers (through the long ciliary nerves)
Nerves of the Orbit
Motor
Sensory
•Optic nerve
•Oculomotor CN III
•Ophthalmic nerve
•Trochlear CN IV
(frontal, lacrimal, nasociliary) •Abducent CN VI
•Zygomatic nerve
Superior division
Inferior division
Sensory Nerves in the Orbit
Optic Nerve
Origin and course
• Formed of axons of ganglion cells of the retina
• Pierces the sclera 4 mm medial to the center of the eyeball
• Runs backwards and medially and leaves the orbital cavity
through the optic canal
• Ends in the optic chiasma, medial to the termination of ICA
• The course of the nerve is divided into 3 parts
• Intraorbital part (2.5cm)
• Canalicular part (0.5cm)
• Intracranial part (1cm)
• The intraorbital part is sinuous, to allow free movement of the
eyeball
• The nerve is enclosed by a complete meningeal sheath
• In the optic canal, the opthalmic artery runs below and lateral
to the optic nerve (and within its meningeal sheath)
• The nerve is pierced by the central artery and vein of the
retina, 12 mm behind the eyeball
Ophthalmic
artery
ICA
Optic
chiasma
Branches of the Ophthalmic Nerve
Lacrimal nerve
•The smallest branch of the ophthalmic division of trigeminal
•Enters the orbit through the sup orbital fissure (outside the common tendinous ring)
•Runs forwards and lateral, above the lateral rectus
•Receives a communication from the zygomatico-temporal nerve (which carries secretory fibers to the lacrimal gland
•Supplies the lacrimal gland
•Gives palpebral branches to the lateral part of upper eyelid
Lacrimal nerve
Lacrimal nerve
Frontal nerve
Lacrimal gland
Lev
Palp
Sup
Lateral rectus
Frontal nerve
Zygomaticotemporal nerve
Ophthalmic
nerve
Maxillary
Zygomatic nerve
nerve
Lacrimal nerve
Common tendinous ring
Trochlea
Zygomaticotemporal nerve
Communication between lacrimal
and zygomatico-temporal
Zygomaticotemporal nerve
Frontal Nerve
•
•
•
•
•
The largest branch of ophthalmic nerve
The highest structure in the orbit
Enters the orbit through the superior orbital fissure (outside the common tendinous ring)
Runs forwards beneath the roof, above the levator palpabrae superioris
Terminates by dividing into
Supra-orbital
• supratrochlear nerve, passes above the trochlea to the forehead
nerve
• supraorbital nerve, passes through the supra-orbital foramen to the forehead
Lacrimal nerve
Frontal
nerve
Supraorbital
nerve
Lev
Palp
Sup
Supra-trochlear
nerve
Trochlea
Frontal
nerve
Nasociliary Nerve
• A branch of the ophthalmic nerve
• Enters the orbit through the sup orbital fissure
(inside the common tendinous ring)
• Crosses above the optic nerve from lateral to medial
• Runs along the medial wall of the orbit, between the
superior oblique and medial rectus muscles
• Terminates by dividing into
1. anterior ethmoidal nerve
2. infratrochlear nerve
Infratrochlear nerve
Lacrimal gland
& nerve
Anterior
ethmoidal nerve
Branches:
• Sensory root to the ciliary ganglion
• Long ciliary nerves
(carry sympathetic fibers from the
plexus around ICA to supply
dilator pupillae muscle)
• Posterior ethmoidal nerve
• Anterior ethmoidal nerve
• Infratrochlear nerve
Long ciliary
nerves
Ciliary
ganglion
Posterior
ethmoidal nerve
Nasociliary
nerve
Sensory root to
ciliary ganglion
Posterior ethmoidal nerve
Infratrochlear nerve
• Passes into the posterior ethmoidal canal
• Supplies the mucosa of the posterior
ethmoidal sinus
Lacrimal gland
& nerve
Anterior ethmoidal nerve
• Passes into the anterior ethmoidal canal
• Supplies the mucosa of the anterior and
middle ethmoidal sinuses
• Reaches the anterior cranial fossa
Anterior
• Passes through the cribriform plate of ethmoidal nerve
ethmoid to reach the nose, where it
Long ciliary
divides into:
nerves
-Two internal nasal nerves (medial
and lateral) for the septum and lateral
wall of the nose
Posterior
-External nasal nerve, supplies the ethmoidal nerve
skin on the lower part of the nose
Infratrochlear nerve
Nasociliary
nerve
• Passes below the trochlea to reach the face
• Supplies skin of upper part of the nose and
medial parts of the eyelids
Ciliary
ganglion
Sensory root to
ciliary ganglion
Zygomatic Nerve
•
•
•
•
Branch of the maxillary nerve
Enters the orbit through the inferior orbital fissure
Divides into zygomatico-temporal and zygomatico-facial nerves
The zygomatico-temporal nerve carries parasympathetic secretory fibers from the sphenopalatine
ganglion to the lacrimal gland (via the communication between it and the lacrimal nerve)
Nasociliary nerve
Lacrimal nerve
Frontal nerve
Ophthalmic
nerve
Maxillary
nerve
Mandibular
nerve
Zygomatic
nerve
Zygomaticotemporal nerve
Motor Nerves in the Orbit
Oculomotor nerve CN III:
• Divides into superior and inferior divisions
• Both divisions enter the orbit through the
superior orbital fissure (inside the common
tendinous ring)
• The superior division supplies:
•superior rectus
•levator palpebrae superioris
• The inferior division supplies:
•Medial rectus
•Inferior rectus
•Inferior oblique
Oculomotor
nerve
Superior
division
Superior rectus
Lev palp
superioris
Medial
rectus
Superior
oblique
Inferior
division
NB.
• The nerve to inferior oblique carries the
parasympathetic root to the ciliary ganglion
• These parasympathetic fibers arise from the
Edinger Westphal nucleus in the midbrain
• The postganglionic fibers supply the
constrictor pupillae and the ciliary muscle
Inferior
rectus
Ciliary
ganglion
Inferior
oblique
Trochlear nerve CN IV
• Enters the orbit through the sup orbital fissure (outside the common tend ring)
• Supplies the superior oblique muscle
Trochlear
nerve
Superior
oblique
Abducent nerve CN VI
• Enters the orbit through the sup orbital fissure (inside the common tend ring)
• Passes between the two heads of the lat rectus m and supplies it from its deep surface.
Ciliary Ganglion
Long ciliary nerves
A minute parasympathetic ganglion lateral to the optic nerve
Roots:
•Sensory: from the nasociliary n.
•Parasymp: from the nerve to inferior oblique
•Symp: from the plexus around the ICA
Branches:
•15-20 short ciliary nerves which pierce
the sclera aound the optic nerve
•They carry:
•Sensory fibers: to the cornea and iris
•Parasympathetic fibers: to the sphincter
pupillae and ciliary muscles
•Sympathetic fibers: to the ciliary vessels
Short ciliary nerves
Ciliary
ganglion
ICA
Parasympathetic root
carried by nerve to
inferior oblique
Sympathetic root
(from plexus around ICA)
Ciliary
ganglion
Sensory root
from nasociliary
nerve
Ophthalmic
nerve
Short ciliary nerves
Blood Vessels of the Orbit
Arteries
Veins
•Ophthalmic artery
•Superior ophthalmic vein
•Inferior ophthalmic vein
•Central vein of the retina
Ophthalmic Artery
• A branch of the ICA
• Enters the orbit through the optic canal below and lateral to the optic nerve and within its meningeal sheath
• Crosses above the optic nerve from lateral to medial (accompanied by the nasociliary nerve)
• Runs along the med wall of the orbit below the superior oblique muscle
• Terminates near the medial end of the upper eyelid by dividing into:
1.Supratrochlear artery
Optic nerve
2.Dorsal nasal artery
Ophthalmic artery
Nasociliary
nerve
Ciliary ganglion
Oculomotor nerve
Ophthalmic
nerve
Maxillary
nerve
Supratrochlear a.
Medial palpebral a.
Supraorbital a.
Latearl palpebral a.
(from lacrimal a.)
Dorsal nasal a.
Anterior ethmoidal a.
Zygomatic branches
(from lacrimal a.)
Posterior ethmoidal a.
Posterior ciliary a.
Central retinal a.
Lacrimal a.
Ophthalmic a.
ICA
Branches of the Ophthalmic Artery
• Central artery of the retina: pierces the optic nerve 12mm behind eyeball and
runs through the center of the nerve
• Lacrimal artery: supplies the lacrimal gland and gives:
-Zygomatico-temporal and zygomatico-facial arteries
-Lateral palpebral artery
-Recurrent meningeal branch
• Ciliary arteries
-Posterior ciliary arteries
-Anterior ciliary arteries
• Supraorbital artery, passes out through the supraorbital foramen
• Post ethmoidal artery, passes through the post ethmoidal canal to the anterior
cranial fossa and gives meningeal branches and nasal branches, which reach the
nose through cribriform plate of ethmoid
• Ant ethmoidal artery, passes through the anterior ethmoidal canal to the ant
cranial fossa and gives meningeal branches and nasal branches, which reach the
nose through cribriform plate of ethmoid
• Recurrent meningeal branch, passes backwards through the sup orbital fissure
to the middle cranial fossa
• Medial palpebral artery, superior and inferior to medial parts of eyelids
• Supratrochlear artery, passes above the trochlea to the forehead
• Dorsal nasal artery, passes below the trochlea and anastomoses with the
termination of facial (angular) a.
Ophthalmic Veins
Superior ophthalmic vein:
• Begins behind the medial part of the upper eyelid
• Runs posteriorly with the ophthalmic artery
• Receives tributaries corresponding to branches of the ophthalmic artery.
• Passes through the superior orbital fissure outside the common tend ring
to end in the cavernous sinus
Inferior ophthalmic vein:
• Begins at the ant part of the floor of
the orbit and runs backwards
• Communicates with the pterygoid
plexus of veins throught the inferior
orbital fissure
• Passes through the sup orbital fissure
(outside the common tend ring) and
terminates in the cavernous sinus
Superior
ophthalmic vein
Facial
vein
Cavernous
sinus
Central vein of the retina:
• Runs with the artery in the center of the optic nerve
• Pierces the optic nerve 12 mm behind the eyeball
• Ends in the cavernous sinus
Pterygoid plexus
of veins
Inferior
ophthalmic vein
Structures passing through the superior orbital fissure
(from lateral to medial)
1. Lacrimal n.
2. Frontal n.
Outside the common tendenous ring
3. Trochlear n.
4. Superior div of oculomotor n.
5. Nasociliary n.
Inside the common tend ring
6. Inferior div of oculomotor n.
7. Abducent n.
8. Ophthalmic vein.
Structures passing through
the inferior orbital fissure
•Maxillary nerve (to continue as the infraorbital nerve)
•Zygomatic nerve (branch from the maxillary nerve)
•Infraorbital vessels
•Communication between inferior ophthalmic vein and
pterygoid plexus of veins