2. Introduction Muscles of the eye gives support and mainly involves in the movement of the eye and provides better visual system. It has two types: intraocular and extra ocular muscles 2/13/2016 2Muscles of the eye Gives astonished look Closing of the eye
3. Intraocular muscles Ciliary muscles -helps in accommodation Sphincter pupillae -constricts pupil Dilater pupillae -Dilates pupil IOM changes shape of lens and size of pupil. 2/13/2016 3Muscles of the eye
4. Extraocular muscles(EOM) EOM Oblique muscles Superior oblique Inferior oblique Recti muscles Superior rectus Inferior rectus Medial rectus Lateral rectus LPS 2/13/2016 4Muscles of the eye
5. EOM ORIGIN NERVE SUPPLY Superior rectus Annulus of zinn Occulomotor nerve Inferior rectus Annulus of zinn Occulomotor nerve Lateral rectus Annulus of zinn Abducent nerve Medial rectus Annulus of zinn Occulomotor nerve Superior oblique Annulus of zinn via trochlea Trochlear nerve Inferior oblique Maxillary bone Occulomotor nerve Levator palpebral superiosis Sphenoid bone Occulomotor nerve 2/13/2016 5Muscles of the eye
6. 2/13/2016 6Muscles of the eye
7. Blood supply Arteries: Ophthalmic artery(medial and lateral branch), Lacrimal artery,anterior ciliary arteries Veins: superior and inferior orbital veins 2/13/2016 7Muscles of the eye
8. Insertion The Recti muscles are inserted into the sclera at the different distances from the limbus forming spiral called Spiral of Tillaux 2/13/2016 8Muscles of the eye
9. Actions of Muscles of the eye Muscles of eye Functions Orbicularis oculli closes the eye LPS elevates the upper lid Superior rectus Moves up and in Inferior rectus Moves down and in Lateral rectus Abduction Medial rectus adduction Superior oblique Eye moves down and out Inferior oblique Eye moves up and out 2/13/2016 9Muscles of the eye
10. 2/13/2016 10Muscles of the eye
11. Fig: Monocular movements of the eye Muscles of the eye
12.Muscles of the eye 12 Fig: Binocular movements of the eye
13. Disorders Amblyopia- partial loss of vision in one or both eye Diplopia- perception of two images from single object Strabismus-misalignment of visual axes of two eyes. Nystagmus- involuntary movement of the eyeballMuscles of the eye
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Extrinsic and Intrinsic Eye Muscle Functions
1. Extrinsic and intrinsic muscles of the eye
• Learning objectives
a. Definition
b. Origin and insertion
c. Blood supply
d. Innervation
e. Embryologically
f. Some related
2. Introduction
Orbital muscles
Extraocular muscles of the eyeball
involved in movement of the eyeball
Intraocular muscles
Controls shape of lense and size of pupil
4. 1. Sphincter pupillae
Sphincter pupillae is a circular muscle, about 1
millimeter wide. It is located at the pupillary margin of
iris.
The sphincter muscle contracts the pupil in a circular
motion while the dilator muscles enlarge the pupil by
pulling the iris radially.(diverging from the center)
An area called the iris collarette is the thickest portion
of the iris where the sphincter muscle and dilator
muscle overlap.
5. Cont................
Origin and insertion.
Pupillary margin of iris.
Action
Constriction of pupil (miosis)
Innervation
Parasympathetic fibers of oculomotor nerve (CN III) via short ciliary nerves.
Blood supply
Long posterior ciliary arteries, anterior ciliary arteries (via minor arterial circle)
6. 2=Dilator pupillae muscle
The dilator pupillae muscles is a ring of contractile cells within
the iris. The pupillary dilator consists of a spokelike
arrangement of modified contractile cells called myoepithelial
cells. These cells are stimulated by the sympathetic nervous
system. When stimulated, the cells contract, widening the pupil
and allowing more light to enter the eye.
7. Dilator pupillae muscle
Origin and insertion
outer margins of iris
Action
Dilates the pupil
Innervation
Long Ciliary nerves(sympathetic)
Blood supply
Not found
Embryologically
Both sphincter and dilator muscles originate from
NEUROECTODERM
8. 3=Ciliary muscle
The ciliary muscle occupies the biggest portion
of the ciliary body, which lies between the
anterior border of the choroid and iris.
The contraction of the ciliary muscle loosens
the zonular fibers increasing the convexity of
the lens, which induces accommodation for
near vision.
The ciliary processes are attached to the lens
via zonular fibers. Through this indirect
attachment, the ciliary muscle acts on the lens
facilitating the accommodation.
9. Layers of Ciliary muscle
The Ciliary muscle consists three main layers :-
longitudinal layer is the outermost muscle layer situated
adjacent to the loose connective tissue of the ciliary body.
The middle layer is the radial layer of muscle. It
represents the transition from the longitudinal to the
circular muscle layer.
The annular or circular layer (Müller’s muscle) is the
innermost muscle layer that functions as a sphincter of the
eye.
10. Cont..............
Origin
originates from a protrusion of the sclera (scleral spur)
Insertion
The llongitudinal part inserts onto the anterior one-third of the choroid
The Radial part: inserts connective tissue near the base of the ciliary processe
Action
Accommodation; and regulation of trabecular meshwork pore size
Innervation
Parasympathetic component of oculomotor nerve (CN III)
Blood supply
Long posterior ciliary arteries;(branch of ophthalmic artery)
And drained by vorticose veins
11. Embrylogical of the ciliary muscle
The ciliary muscle developed from the vascular layer of
the mesenchyme Surrounding the optic cup.
12. Extraocular muscles
Has two types :
Voluntary
1. Levator pulpebrae superioris
2. Superior rectus
3. Inferior rectus
4. Medial rectus
5. Lateral rectus
6. Superior oblique
7. IInferior oblique
Involuntary
1. Superior tarsal muscle
2. Inferior tarsal muscle
3. Orbitalis
14. 1=Levator pulpebrae superioris
1=The levator pulpebrae superioris, Does not act on eyeball but iit's Responsible
for elevating the upper eyelid
Length 60mm long
Muscle 40mm
Tendon 14-20mm
15. Cont.......
Origin
Lesser wing of sphenoid bone
Action
Elevation of the upper muscle
Innervation
a) Voluntary part :superior division of oculomotor nerve
b) Involuntary part:sympathetic innervation from the carotid plexus whose
fibers join the oculomotor nerve
Blood supply
Receives from ophthalmic artery and it's branch via supraorbital branch
16. Insertion (aponeurosis of the muscle splits into 3 lamina)
Upper lamina (voluntary) is inserted iinto the skin of upper lid
Middle lamina.(involuntary) atached to upper margin of superior
Lower lamina (involuntary)is attached to Superior conjunctival fornix
Embrylogical
At 2.5 months' gestation, the levator
palpebrae superioris develops. It
separates from the superior rectus
muscle at the fourth month of
gestation. Clinically, failure of
separation of these muscles would
result in congenital ptosis.
17. 2=Superior rectus muscle
Length=41.8mm long
Tendon=5.8mm long
Wide=10.6mm
Origin
Annulus of zinn
Insertion
Superiorly about 7.7mm from
limbus
•Action
• Elevates, adducts, internally rotates
eyeball
•Blood supply
• muscular branch of ophthalmic artery
•Innervation
• Superior division of CN III
• Expansion of the SR is attached to the
LPS. Thus when the SR makes the eye
look up the upper lid is also raised.
18.
19. 3=inferior rectus muscle
• Length=4omm long
• Tendon=5.5mm long
• Wide=9.8mm
•Origin
• Annulus of zinn
•Insertion
• inferiorly about 6.5mm from
limbus
• Action
• Depresses, adducts, externally
rotates eyeball
• Blood supply
• muscular branch of ophthalmic
artery and infraorbital artery
• Innervatio
• InfeInferior division of CN III
(oculomotor)
20. 4=medial rectus muscle
• Length=4o.8mm long
Tendon=3.7mm long
• Wide=10.3mm
Origin
• Annulus of zinn
• Insertion
• Medially about 5.5mm from
limbus
•Action
• Adducts the eyeball
•Blood supply
• muscular branch of ophthalmic
artery
Innervation
• InfeInferior division of CN III
(oculomotor)
21. Facial expantion of the sheaths (muscular fascia)
of the medial rectus attached to the zygomatic
bone.
22. 5=lateral rectus muscle
Length=4o.6mm long
Tendon=8mm long
Wide=9.2mm
Origin
• Annulus of zinn
Insertion
• laterally about 6.9 mm from
limbus from limbus
Action
• Abducts the eyeball
•Blood supply
• muscular branch of ophthalmic
artery and lacrimal artery
•Innervation
• CN VI (abducens)
23. Facial expantion of the sheaths (muscular fascia)
of the lateral rectus attached to the zygomatic
bone.
24. 6=Superior oblique muscle
Length=4omm long
Tendon=20mm long
Wide=10.8mm
Origin
• Medial to optic foramen, between
annulus of zinn and periorbita
Insertion
• Through pulley(trochlea) ends
superolateral aspect of eyeball.
Action
Abducts, depresses, internally
rotates eyeball
•Blood supply
muscular branch of ophthalmic
artery
Innervation
• CN IV (trochlear)
25. 7=inferior oblique muscle
• Length=37mm long
• Tendon=1mm long
• Wide=9.6mm
• Origin
• Orbital surface of maxilla.
• Insertion
• Inferolateral aspect of eyeball
(deep to lateral rectus muscle)
•Action
• Abducts, depresses, internally
rotates eyeball
•Blood supply
• muscular branch of ophthalmic
artery
•Innervation
• CN IV (trochlear)
28. 1=Superior tarsal muscle
Superior tarsal (Muller's muscle) is a small muscle found within
the superior eyelid. It is a smooth muscle, but it is considered as a
structural component of the larger skeletal muscle of the eyelid;
levator palpebrae superioris.
29. Cont........
Origin
Deep surface of levator palpebrae superioris muscle
Insertion
Superior tarsal plate of the eyelid
Action
Elevates and retracts the upper eyelid
Innervation
Sympathetic nervous system (via internal carotid plexus)
Blood supply
Ophthalmic artery.
30. 2=Inferior tarsal muscle
The inferior tarsal muscle :is commonly described as a part of the
capsulopalpebral fascia and the smooth muscle fibers under the
fornix adjacent to the capsulopalpebral fascia
.The inferior tarsal muscle of the lower eyelid is a homologous
organ with the Müller muscle of the upper eyelid.
31.
32. Cont.....
Origin
Capsulopalpebral fascia
Insertion
Inferior tarsal plate
Action
Lower lid retraction
Innervation
sympathetic nervous system like the Müller muscle.
Blood supply
Not found
33. 3=orbitalis muscle
• The orbitalis muscle is a vestigial or rudimentary nonstriated
muscle (smooth muscle) that crosses from the infraorbital
groove and sphenomaxillary fissure and is intimately united with
the periosteum of the orbit.
34. About orbitalis muscle
• Vestigial muscle
• Crosses inferior orbital fissure and sphenomaxiliary fissure
• Unites with periosteum of orbit
Action
Forward protrusion of orbit
Innervation
Sympathetic nervous system (via internal carotid plexus)
35. • Embreologically of EOM
All the extraocular muscles develope from mesodermal
mesenchymal tissue