Eye Anatomy

1. The Orbital Region
(Bony Orbit, Ocular Muscles, Lacrimal & Ciliary
Gland And Eyeball)
Dr. Rabia Inam Gandapore
Assistant Professor
Head of Department Anatomy
(Dentistry-BKCD)
B.D.S (SBDC), M.Phil. Anatomy (KMU),
Dip. Implant (Sharjah, Bangkok, ACHERS) , CHPE
(KMU),CHR (KMU), Dip. Arts (Florence, Italy)

2. Teaching Methodology
 LGF (Long Group Format)
 SGF (Short Group Format)
 LGD (Long Group Discussion, Interactive discussion with the use of models or diagrams)
 SGD (Short Group)
 SDL (Self-Directed Learning)
 DSL (Directed-Self Learning)
 PBL (Problem- Based Learning)
 Online Teaching Method
 Role Play
 Demonstrations
 Laboratory
 Museum
 Library (Computed Assisted Learning or E-Learning)
 Assignments
 Video tutorial method

3. Goal/Aim (main objective)
 To help/facilitate/augment the students about the:
1. Describe walls and openings in the orbital cavity.
2. Enumerate foramen and fissures in bony orbit and structures passing through it.
3. Explain origin, insertion, nerve supply and action of extra-ocular muscles
4. Discuss lacrimal and ciliary glands.
5. Describe features & relevant clinical anatomy of:
• Outer Coat
• Cornea
• Middle Coat
• Inner Coat
• Aqueous Humour
• Vitreous Body

4. Specific Learning Objectives (cognitive)
At the end of the lecture the student will able to:
1. Recognize the gross anatomical features of the
Describe walls and openings in the orbital cavity.
2. Enumerate foramen and fissures in bony orbit and structures passing through it.
3. Explain origin, insertion, nerve supply and action of extra-ocular muscles
4. Discuss lacrimal and ciliary glands.
5. Describe features & relevant clinical anatomy of:
• Outer Coat
• Cornea
• Middle Coat
• Inner Coat
• Aqueous Humour
• Vitreous Body
6. Sketch labeled diagram of the Eyeball & tabulated extra-ocular muscles

5. Psychomotor Objective: (Guided response)
 A student to draw labelled diagram of Eyeball & tabulated extra-ocular muscles

6. Affective domain
 To be able to display a good code of conduct and moral values in the class.
 To cooperate with the teacher and in groups with the colleagues.
 To demonstrate a responsible behavior in the class and be punctual, regular, attentive and
on time in the class.
 To be able to perform well in the class under the guidance and supervision of the teacher.
 Study the topic before entering the class.
 Discuss among colleagues the topic under discussion in SGDs.
 Participate in group activities and museum classes and follow the rules.
 Volunteer to participate in psychomotor activities.
 Listen to the teacher's instructions carefully and follow the guidelines.
 Ask questions in the class by raising hand and avoid creating a disturbance.
 To be able to submit all assignments on time and get your sketch logbooks checked.

7. Lesson contents
Clinical chair side question: Students will be asked if they know what is the function of Eyeball
Outline:
 Activity 1 The facilitator will explain the student's to Recognize the
 Gross anatomical features and openings in the orbital cavity.
 Enumerate foramen and fissures in bony orbit and structures passing through it.
 Explain origin, insertion, nerve supply and action of extra-ocular muscles
 Discuss lacrimal and ciliary glands.
 Describe features & relevant clinical anatomy of: • Outer Coat • Cornea • Middle Coat • Inner Coat •
Aqueous Humour • Vitreous Body
 Activity 2 The facilitator will ask the students to make a labeled diagram of the Sketch labeled diagram of
the Eyeball & tabulated extra-ocular muscles
 Activity 3 The facilitator will ask the students a few Multiple Choice Questions related to it with flashcards.

8. Recommendations
 Students assessment: MCQs, Flashcards, Diagrams labeling.
 Learning resources: Langman’s T.W. Sadler, Laiq Hussain Siddiqui, Snell Clinical Anatomy, Netter’s
Atlas, BD Chaurasia’s Human anatomy, Internet sources links.

9. Orbital Region
 EYELIDS
 MOVEMENTS OF EYELIDS

10. Orbital Region
 Orbits are a pair of bony cavities that
contain:
1. Eyeballs
2. Associated muscles, nerves, vessels
3. Fats
4. Lacrimal apparatus.
 Eyelids: Orbital opening is guarded by 2 thin,
movable folds.
 protect eye from injury & excessive light by
their closure

11. Eyelids
a. Upper eyelid: is larger & more mobile.
 Eye closed: it completely covers cornea of eye.
 Eye open: looking straight ahead it covers upper margin
of cornea.
a. Lower eyelid: smaller & less mobile.
 When eye open: lies just below cornea
 When eye closed: rises only slightly.
 Upper & Lower eyelids: meet at medial & lateral angles.
 Palpebral fissure: elliptical opening between eyelids & is
the entrance into conjunctival sac.

13.  Superficial surface of eyelids: covered by skin
 Deep surface: covered by mucous membrane called Conjunctiva.
 Eyelashes: short, curved hairs on free edges of eyelids, arranged in double or triple
rows at mucocutaneous junction.
 Sebaceous glands (glands of Zeis): open directly into eyelash follicles.
 Ciliary glands (glands of Moll): modified sweat glands, open separately between
adjacent lashes.
 Tarsal glands: long, modified sebaceous glands that pour their oily secretion onto
margin of lid; their openings lie behind eyelashes. This oily material prevents
overflow of tears & helps make the closed eyelids airtight.

16.  Lacus lacrimalis: small space which separates more rounded
medial angle from eyeball
 Caruncula lacrimalis: small, reddish yellow elevation in center
of Lacus lacrimalis
 Plica semilunaris: reddish semilunar fold, lies on lateral side of
caruncle.
 Papilla lacrimalis: Near medial angle of eye a small elevation. It
projects into lacus
 Punctum lacrimale: On summit of papilla is a small hole which
leads into canaliculus lacrimalis.
 Punctum & Canaliculus carry tears down into the nose

19.  Conjunctiva: thin mucous membrane that lines eyelids & is
reflected at superior & inferior fornices onto anterior surface
of eyeball. Its epithelium is continuous with that of cornea.
 Upper lateral part of superior fornix: pierced by ducts of
lacrimal gland.
 Conjunctival sac: Conjunctiva forms potential space, it opens
at palpebral fissure.
 Subtarsal sulcus: Beneath eyelid groove, it runs close to &
parallel with margin of lid. It tends to trap small foreign
particles introduced into conjunctival sac & clinically important

21.  Framework of eyelids: formed by fibrous sheet, orbital septum. Its attached to
periosteum at orbital margins.
 Tarsal Plates: is thickened at margins of lids to form; superior & inferior tarsal
plates.
 Lateral palpebral ligament: lateral ends of plates are attached by a band to a
bony tubercle just within orbital margin.
 Medial palpebral ligament: medial ends of plates are attached by a band to crest
of lacrimal bone.
 Tarsal glands: are embedded in posterior surface of tarsal plates.
 Orbicularis oculi muscle: superficial surface of tarsal plates & orbital septum are
covered by its palpebral fibers.
 aponeurosis of insertion of Levator palpebrae superioris muscle pierces the
orbital septum to reach anterior surface of superior tarsal plate & skin.

23. Movements of the Eyelids
 Position of eyelids at rest depends on tone of:
a. Orbicularis oculi muscles
b. Levator palpebrae superioris muscles
c. Position of eyeball.
 Eyelids are closed by:
a. Contraction of: orbicularis oculi muscles
b. Relaxation of: levator palpebrae superioris
muscles.
 Eye is opened by:
a. Levator palpebrae superioris raising upper lid.
 On looking upward:
a. levator palpebrae superioris contracts
b. upper lid moves with eyeball.
 On looking downward:
a. Both lids move
b. Upper lid continues to cover upper part of cornea
c. Lower lid is pulled downward by conjunctiva, its
attached to sclera & lower lid.

24. Muscles of Eyeball & Eyelids
 ORIGIN
 INSERTION
 ACTION
 NERVE SUPPLY

25. Extrinsic Muscles
 6 voluntary muscles that run from posterior wall of orbital cavity to eyeball:
1. Superior rectus: to raise cornea upward, inferior oblique muscle must assist
2. Inferior rectus: inferior rectus to depress cornea downward, superior oblique
muscle must assist.
 Superior & inferior recti are inserted on medial side of vertical axis of eyeball, they
not only raise & depress cornea, respectively, but also rotate it medially.
3. Medial rectus
4. Lateral rectus
5. Superior oblique muscles
6. Inferior oblique muscles.

26. Movements of Eyeball
Center of cornea or pupil: is used as
anatomic “anterior pole” of eye
 Elevation: rotation of eye upward
 Depression: rotation of eye downward
 Abduction: rotation of eye laterally
 Adduction: rotation of eye medially
 Rotatory movements: use upper rim of
cornea (or pupil) as marker. Eye rotates:
a. Medially
b. Laterally.

27. S.
No.
Muscles Origin Insertion Nerve
Supply
Action
Extrinsic Muscles of Eyeball (Striated Skeletal Muscle)
1. Superior
Rectus
Tendinous
ring on
posterior
wall of orbital
cavity
Superior surface of eyeball just
posterior to corneoscleral junction
Oculomotor
nerve (3rd
cranial nerve)
Raises cornea
upward and medially
2. Inferior
Rectus
Inferior surface of eyeball just
posterior to corneoscleral junction
Depresses cornea
downward and
medially
3. Medial Rectus Medial surface of eyeball just
posterior to corneoscleral junction
Rotates eyeball so
that cornea looks
medially
4. Lateral Rectus Lateral surface of eyeball just
posterior to corneoscleral junction
Abducent
nerve (6th
cranial nerve)
Rotates eyeball so
that cornea looks
laterally
5. Superior
Oblique
Posterior
wall of orbital
cavity
Passes through pulley and is
attached to superior surface of
eyeball beneath superior rectus
Trochlear
nerve (4th
cranial nerve)
Rotates eyeball so
that cornea looks
downward and
laterally
6. Inferior
Oblique
Floor of
orbital cavity
Lateral surface of eyeball deep to
lateral rectus
Oculomotor
nerve (3rd
cranial nerve)
Rotates eyeball so
that cornea looks
upward and laterally

30. Intrinsic Muscles
 Involuntary ciliary muscle
 Constrictor & Dilator pupillae of
iris: take no part in movement of
eyeball

31. S. No. Muscles Origin Insertion Nerve Supply Action
Intrinsic Muscles of Eyeball (Smooth Muscle)
1. Sphincter pupillae of iris Parasympathetic
via oculomotor
nerve
Constricts pupil
2. Dilator pupillae of iris Sympathetic Dilates pupil
3. Ciliary muscle Parasympathetic
via oculomotor
nerve
Controls shape of
lens; in
accommodation,
makes lens more
globular
Muscles of Eyelids
1. Orbicularis Oculi
2. Levator palpabrae superioris Back of
orbital
cavity
Anterior
surface and
upper margin
of superior
tarsal plate
Striated muscle
oculomotor nerve,
smooth muscle
sympathetic
Raises upper lid

32. Fascial Sheath of Eyeball
 Surrounds eyeball from optic nerve to corneoscleral junction.
 It separates eyeball from orbital fat & provides it with a socket for free movement.
 It is perforated by tendons of orbital muscles & is reflected onto each of them as a
tubular sheath.
 Sheaths for tendons of medial & lateral recti are attached to medial & lateral walls of orbit
by triangular ligaments called medial & lateral check ligaments.
 Lower part of fascial sheath, which passes beneath the eyeball & connects the check
ligaments, is thickened & serves to suspend eyeball; its called suspensory ligament of
eye & is suspended from medial & lateral walls of orbit, as if in a hammock.

40. Lacrimal Appratus
 LACRIMAL GLANDS
 LACRIMAL DUCTS

41. Lacrimal Apparatus
Lacrimal Gland
 consists of:
a. Orbital part: large
b. Palpebral part: small
which are continuous with each other around lateral
edge of aponeurosis of levator palpebrae
superioris.
 It is situated above eyeball in anterior & upper part
of orbit, posterior to orbital septum.
 It opens into lateral part of superior fornix of
conjunctiva by 12 ducts.

43.  Parasympathetic secretomotor nerve: supply is derived from lacrimal nucleus of
facial nerve.
a. Preganglionic fibers: reaches pterygopalatine ganglion (sphenopalatine
ganglion) via nervus intermedius & its great petrosal branch and via nerve of
pterygoid canal.
b. Postganglionic fibers: leave ganglion & joins maxillary nerve. It then pass into
its zygomatic branch a& zygomaticotemporal nerve. They reach lacrimal gland
within lacrimal nerve.
 Sympathetic postganglionic nerve supply is from internal carotid plexus &
travels in deep petrosal nerve,nerve of pterygoid canal, maxillary nerve, zygomatic
nerve, zygomaticotemporal nerve & lacrimal nerve.

49. Lacrimal Ducts
 Tears circulate across cornea & accumulate in lacus lacrimalis.
 tears enter canaliculi lacrimales through puncta lacrimalis.
 canaliculi lacrimales pass medially & open into lacrimal sac, which lies in the
lacrimal groove behind medial palpebral ligament & is the upper blind end of the
nasolacrimal duct.
 Nasolacrimal duct: 0.5 in. (1.3 cm) long & emerges from lower end of lacrimal sac.
 Duct descends downward, backward & laterally in a bony canal & opens into
inferior meatus of nose.
 opening is guarded by a fold of mucous membrane known as lacrimal fold. This
prevents air from being forced up the duct into lacrimal sac on blowing nose

53. The Orbit
 OPENINGS INTO THE ORBITAL CAVITY
 ORBITAL FASCIA

54. The Orbit
 Pyramidal cavity:
Base: Anterior Apex: Posterior.
 Orbital margin above: frontal bone
 Lateral margin: processes of frontal & zygomatic bones
 Inferior margin: zygomatic bone & maxilla
 Medial margin: processes of maxilla & frontal bone.
Roof: orbital plate of frontal bone (separates orbital cavity from anterior cranial fossa & frontal lobe of
cerebral hemisphere)
Lateral wall: zygomatic bone & greater wing of sphenoid
Floor: orbital plate of maxilla ( separates orbital cavity from maxillary sinus)
Medial wall: before backward by frontal process of maxilla, lacrimal bone, orbital plate of ethmoid
(which separates orbital cavity from ethmoid sinuses) & body of sphenoid

55. Openings into the Orbital Cavity
Orbital opening: Lies anteriorly. About one sixth of eye is exposed; the remainder is protected by walls of orbit. The
openings into orbital cavity are:
 Supraorbital notch (Foramen): situated on superior orbital margin. It transmits supraorbital nerve & blood vessels
 Infraorbital groove & canal: Situated on floor of orbit in orbital plate of maxilla; they transmit infraorbital nerve (a
continuation of maxillary nerve) & blood vessels.
 Nasolacrimal canal: Located anteriorly on medial wall; it communicates with inferior meatus of nose. It transmits
nasolacrimal duct.
 Inferior orbital fissure: Located posteriorly between maxilla & greater wing of sphenoid; it communicates with
pterygopalatine fossa. It transmits maxillary nerve & its zygomatic branch, inferior ophthalmic vein & sympathetic nerves.
 Superior orbital fissure: Located posteriorly between greater & lesser wings of sphenoid; it communicates with the
middle cranial fossa. It transmits the lacrimal nerve, frontal nerve, trochlear nerve, oculomotor nerve (upper & lower
divisions), abducent nerve, nasociliary nerve & superior ophthalmic vein.
 Optic canal: Located posteriorly in lesser wing of sphenoid; it communicates with middle cranial fossa. It transmits optic
nerve & ophthalmic artery.

57. Orbital Fascia
 Is periosteum of bones that form walls of
orbit.
 It is loosely attached to bones & is
continuous through foramina & fissures with
the periosteum covering outer surfaces of
bones.
 Muscle of Müller, or orbitalis muscle: thin
layer of smooth muscle that bridges inferior
orbital fissure. Its supplied by sympathetic
nerves & its function is unknown.

58. The Eyeball
 MOVEMENTS OF EYEBALL
 FACIAL SHEATH OF EYEBALL
 STRUCTURE AND COATS OF THE EYEBALL
a. FIBROUS COAT
b. VASCULAR PIGMENTED COAT
c. NERVOUS COAT
 CONTENTS OF THE EYEBALL

59. Structure of Eye
 Embedded in orbital fat but is separated from it by fascial sheath of eyeball.
 Eyeball consists of 3 coats:
1. Fibrous coat
2. Vascular pigmented coat
3. Nervous coat.

61. Coats of Eyeball
1. Fibrous Coat: made up of a
a. Posterior opaque part: Sclera
b. Anterior transparent part: Cornea.

62. a. The Sclera
 Opaque sclera is composed of dense fibrous tissue & is white.
 Posteriorly, its pierced by optic nerve & is fused with dural sheath of that nerve.
 Lamina cribrosa is area of sclera that is pierced by nerve fibers of optic nerve.
 Its also pierced by ciliary arteries & nerves & associated veins; venae
vorticosae.
 Its directly continuous in front with cornea at corneoscleral junction, or limbus.

64. b. Cornea
 Transparent cornea is largely responsible for refraction of light entering eye.
 Its in contact posteriorly with aqueous humor.
 Blood Supply: avascular & devoid of lymphatic drainage. Its nourished by
diffusion from aqueous humor & from capillaries at its edge.
 Nerve Supply: Long ciliary nerves from ophthalmic division of trigeminal nerve
 Function of Cornea: refractive medium of eye. This refractive power occurs on the
anterior surface of cornea, where refractive index of cornea (1.38) differs greatly
from that of air. The importance of tear film in maintaining normal environment for
corneal epithelial cells should be stressed.

66. 2. Vascular Pigmented Coat
Consists, from behind forward, of:
a. Choroid: composed of an:
 Outer: pigmented layer
 Inner: highly vascular layer
b. Ciliary body
c. Iris

67. b. Ciliary Body:
 continuous:
 Posteriorly with choroid
 Anteriorly it lies behind peripheral margin of iris.
 Its composed of:
1. Ciliary ring: posterior part of body & its surface has shallow grooves; ciliary striae.
2. Ciliary processes: are radially arranged folds, or ridges, to posterior surfaces of which
are connected the suspensory ligaments of lens
3. Ciliary muscle: composed of meridianal & circular fibers of smooth muscle.
a. Meridianal fibers: run backward from region of corneoscleral junction to ciliary
processes.
b. Circular fibers: are fewer in number & lie internal to meridianal fibers.

70.  Nerve supply: ciliary muscle is supplied by
parasympathetic fibers from oculomotor nerve. After
synapsing in ciliary ganglion, postganglionic fibers pass
forward to eyeball in short ciliary nerves.
 Action: Contraction of ciliary muscle, especially meridianal
fibers, pulls ciliary body forward. This relieves tension in
suspensory ligament, & elastic lens becomes more
convex. This increases refractive power of lens

72. c. Iris & Pupil
 Iris: contractile, pigmented diaphragm
 Pupil: central aperture
 Its suspended in aqueous humor between cornea & lens.
 Periphery of iris is attached to anterior surface of ciliary body.
 It divides the space between lens & cornea into an
1. Anterior Chamber
2. Posterior Chamber
 Muscle fibers of iris are involuntary & consist of circular & radiating fibers.
a. Circular fibers: form sphincter pupillae & are arranged around margin of pupil.

76.  Nerve supply:
a. Sphincter pupillae: is supplied by parasympathetic fibers from
oculomotor nerve. After synapsing in ciliary ganglion, postganglionic
fibers pass forward to eyeball in short ciliary nerves.
b. Dilator pupillae: is supplied by sympathetic fibers, which pass
forward to eyeball in long ciliary nerves.
 Action:
a. Sphincter pupillae: constricts pupil in presence of bright light & during
accommodation.
b. Dilator pupillae: dilates pupil in presence of light of low intensity or in
presence of excessive sympathetic activity such as occurs in fright.

78. 3. Nervous Coat: The Retina
 Retina consists of an:
a. Outer pigmented layer: contact with choroid
b. Inner nervous layer: contact with the vitreous body
 Posterior 3 quarters of retina is receptor organ.
 Its anterior edge forms a wavy ring; ora serrata, &
nervous tissues end here.
 Anterior part of retina is nonreceptive & consists of
pigment cells, with a deeper layer of columnar epithelium.
It covers ciliary processes & back of iris.

81.  At the center of posterior part of retina is an oval, yellowish area; macula lutea, which is
area of retina for the most distinct vision.
 It has a central depression; fovea centralis.
 Optic nerve leaves retina about 3 mm to medial side of macula lutea by optic disc.
 Optic disc is slightly depressed at its center, where its pierced by central artery of
retina.
 At optic disc is a complete absence of rods & cones so that it is insensitive to light & is
referred to as the “blind spot.”
 Ophthalmoscopic examination: optic disc is seen to be pale pink in color, much paler
than surrounding retina.

84. Contents of Eyeball
 consist of:
a. Refractive media
b. Aqueous humor
c. Vitreous body
d. Lens.

85. a. Aqueous Humor
 Clear fluid that fills anterior & posterior chambers of eyeball .
 It’s a secretion from ciliary processes, via it enters posterior chamber.
 It flows into anterior chamber through pupil & is drained away through spaces at the
iridocorneal angle into canal of Schlemm
 Obstruction: to draining of aqueous humor results in a rise in intraocular pressure
called glaucoma.
 This can produce degenerative changes in retina i.e. blindness.

86. Function Of Aqueous Humor
 To support wall of eyeball by exerting internal pressure
 maintaining its optical shape.
 It also nourishes cornea & lens
 removes products of metabolism;
Note: cornea & lens do not possess a blood supply.

87. b. Vitreous Body
 fills eyeball behind the lens & is
a transparent gel.
 Hyaloid canal is a narrow
channel that runs through the
vitreous body from the optic disc
to posterior surface of lens; in
fetus, it is filled by the hyaloid
artery, which disappears before
birth.

89. Function of vitreous body
 Contribute slightly to magnifying power of eye.
 Supports posterior surface of lens
 Assists in holding neural part of retina against
pigmented part of retina.

90. C. The Lens
 transparent, biconvex structure enclosed in a transparent capsule.
 Its situated behind iris & in front of vitreous body & is encircled by ciliary processes.
 Lens consists of an elastic capsule, which envelops the structure; a cuboidal
epithelium, which is confined to anterior surface of lens; & lens fibers, which are
formed from cuboidal epithelium at equator of lens.
 Lens fibers make up bulk of lens.
 Elastic lens capsule is under tension, causing lens constantly to endeavor to
assume a globular rather than a disc shape.
 Lens is attached to ciliary processes of ciliary body by suspensory ligament.
 The pull of radiating fibers of suspensory ligament tends to keep the elastic lens
flattened so that eye can be focused on distant objects..

93. Accommodation of the Eye
 To accommodate eye for close objects, ciliary muscle contracts & pulls
ciliary body forward & inward so that radiating fibers of suspensory ligament
are relaxed.
 This allows elastic lens to assume a more globular shape.
 With advancing age: lens becomes denser & less elastic,& ability to
accommodate is lessened (presbyopia).
 This disability can be overcome by use of an additional lens in form of glasses
to assist the eye in focusing on nearby objects.

94.  Constriction of Pupil during Accommodation of Eye
To ensure that light rays pass through central part of lens so spherical aberration is
diminished during accommodation for near objects, the sphincter pupillae muscle
contracts so pupil becomes smaller.
 Convergence of Eyes during Accommodation of Lens
In humans, retinae of both eyes focus on only one set of objects (single binocular
vision). When an object moves from a distance toward an individual, the eyes
converge so that a single object, not two, is seen. Convergence of eyes results
from coordinated contraction of medial rectus muscles.

95. Clinical Correlations

97. Clinical Testing for Actions of Superior & Inferior
Recti AND Superior & Inferior Oblique Muscles
 Physician tests eye movements: Patient is asked to look vertically upward or
downward. Example: Origins of superior & inferior recti are situated about 23°
medial to their insertions so when the patient is asked to turn cornea laterally, these
muscles raise (superior rectus) or lower (inferior rectus) cornea.
 Test for Superior Oblique: ask patient to look medially & downward at tip of his or
her nose.
 Test for inferior Oblique: asking patient to look medially & upward. Because lateral
& medial recti are simply placed relative to eyeball, asking patient to turn cornea
directly laterally tests lateral rectus & turning cornea directly medially tests medial
rectus.

99. Eye Trauma
 Eyeball: well protected by bony orbit but provides no protection
from small objects i.e. golf balls & cause severe damage on lateral
side.
 Blowout fractures of orbital floor involving maxillary sinus
occur due to blunt force to face. If the force is applied to eye, the
orbital fat explodes inferiorly into maxillary sinus, fracturing orbital
floor. Not only can blowout fractures cause displacement of
eyeball, but cause double vision (diplopia), injure infraorbital
nerve, producing loss of sensation of skin of cheek & gum on
that side. Entrapment of inferior rectus muscle in fracture may
limit upward gaze.

100. Strabismus
 Many cases of strabismus are
non-paralytic
 caused by an imbalance in action
of opposing muscles. This type of
strabismus is known as
concomitant strabismus
 common in infancy.

101. Pupillary Reflexes
 Reaction of pupils to light & accommodation: depend on integrity of nervous
pathways.
1. Direct light reflex:
 Normal pupil reflex contracts when a light is shone into patient’s eye.
 Nervous impulses pass from retina along optic nerve to optic chiasma & optic tract
 Before reaching lateral geniculate body, fibers leave the tract & pass to oculomotor
nuclei on both sides via pretectal nuclei.
 From parasympathetic part of nucleus, efferent fibers leaves midbrain in the
oculomotor nerve & reach the ciliary ganglion via nerve to inferior oblique.
 Postganglionic fibers pass to constrictor pupillae muscles via short ciliary nerves.

103. 2. Consensual light reflex
 Tested by shining light in one eye &
noting contraction of pupil in opposite
eye.
 This reflex is possible because the
afferent pathway just described travels
to parasympathetic nuclei of both
oculomotor nerves.

104. 3. Accommodation reflex
 is contraction of pupil that occurs when a person suddenly
focuses on a near object after having focused on a
distant object.
 Nervous impulses pass from retina via optic nerve, optic
chiasma, optic tract, lateral geniculate body, optic
radiation & cerebral cortex of occipital lobe of brain.
 Visual cortex is connected to eye field of frontal cortex.
From here, efferent pathways pass to parasympathetic
nucleus of oculomotor nerve. From there, efferent
impulses reach constrictor pupillae via oculomotor
nerve, ciliary ganglion & short ciliary nerves.

105. Horner’s Syndrome

106. Thank You