This is an educational presentation on contents of orbit. The presentation includes anatomy of bony orbit, eyelids, conjunctiva, lacrimal glands and extra ocular muscles with their action explained in detail.

1. Dr. Ayshah Hashimi

2. ORBIT OF EYE
The bony orbits (or eye sockets) are bilateral and
symmetrical cavities in the head. They enclose the eyeball and its
associated structures.
7 Bones that forms orbit
1. Maxilla 5. Ethmoid
2. zygomatic bone 6. Palatine bone
3. Frontal bone 7. Lacrimal bone
4. Sphenoid
Boundaries
• Superiorly- Frontal Bone
• Medially- Frontal process of Maxilla
• Laterally- Frontal process of Zygomatic Bone
Maxilla
Zygomatic
Frontal
Sphenoid Ethmoid
Palatine
Lacrimal

3. Openings Structure
Supraorbital Foramen Supraorbital vessels and nerve
Infraorbital Groove Infraorbital vessels and nerve
Nasolacrimal Canal Nasolacrimal duct
Superior Orbital fissure 3rd, 4th, 5th, 6th cranial nerve, Superior
ophthalmic vein
Inferior Orbital fissure Maxillary nerve, inferior ophthalmic vein
Anterior ethmoidal
foramen
Anterior ethmoidal vessels and nerve
Posterior ethmoidal
foramen
Posterior ethmoidal vessels and nerve
Supraorbital Foramen
Infraorbital Groove
Superior Orbital fissure
Inferior Orbital fissure
Anterior/Posterior
ethmoidal foramen
Optic Canal
Openings In Orbit

4. CONTENTS OF ORBIT
• Fascia (orbital and Bulbar)
• ocular muscles
• Eyelids
• Lacrimal glands
• Eyeballs
• Nerves (optic, oculomotor, trochlear, abducent, branches of ophthalmic and maxillary nerves and sympathetic nerves )
• Blood vessels (ophthalmic artery, superior and inferior ophthalmic veins and lymphatics)
Visual Axis and Orbital axis
Visual Axis- Axis passing through centres of anterior and posterior poles of the eye ball
Orbital Axis- Axis passing through optic canal and centre of base of orbit

5. Orbital Fat
Free space in orbit that is not occupied by eyeball and extraocular muscles have fatty tissue
2 Fascia of eye
1. Orbital fascia/periorbita: It forms the periosteum of the bony orbit. It also forms orbital septum
2. Tenon’s Capsule/Bulbar Fascia- thin loose membranous sheath around the eyeball extending
from the optic nerve to the sclerocorneal junction or limbus.
Orbital fascia
Orbital Septum
Tenon’s Capsule

6. Tenon’s capsule gives off number of expansions covering each orbital muscle and forming medial and lateral check ligament,
below these 2 ligaments unite to form suspensory ligament of the eye or Lockwood. Above it forms medial palpebral ligament
Medial Check Ligament
Lateral Check Ligament
Suspensory Ligament of Lockwood
Medial Palpebral Ligament

7. Ocular muscle
There are 2 types of muscle
• Extraocular/Voluntary muscle
4 Recti
 Superior Rectus
 Inferior Rectus
 Medial Rectus
 Lateral Rectus
2 Oblique
 Superior Oblique
 Inferior Oblique
 Levator palpebrae superioris
• Intraocular/Involuntary muscle
 Ciliary muscle
 Sphincter pupillae
 Dilator pupillae

8. Origin and Insertion of extraocular muscles
The 4 recti muscles arises from common annular tendon or tendinous ring and are inserted into the
sclera.
Nerve supply
Superior oblique 4th cranial nerve (Trochlear)
Lateral rectus 6th cranial nerve (Abducent)
Rest all extraocular muscle 3rd cranial nerve (Oculomotor)
Movement
 Superior Rectus- Elevation, Adduction, Intorsion
 Inferior Rectus- Depression, Adduction, Extorsion
 Medial Rectus- Only Adduction
 Lateral Rectus- Only Abduction
 Superior Oblique- Intorsion, Depression, Abduction
 Inferior Oblique- Extorsion, Elevation, Abduction
Elevation
Depression
Adduction
Abduction
Excyclotorsion
Incyclotorsion

9. GUESS THE MUSCLE INVOLVED?

10. Eyelids
• Eyelids are thin movable curtains composed of skin on their anterior surface and mucus membrane (conjunctiva) on the
posterior surface
• Mobile curtains (act as shutter)
• Spread tera film over the cornea
• Contribution to facial features
• Position relays information- wake/Asleep
• Position of lids- When the eye is open, the upper lid covers about one-sixth of the cornea and the lower lid just touches
the limbus
• Canthi- The two lids meet each other at medial and lateral angles
• Palpebral aperture- It is the elliptical space between the upper and the lower lid

11. Layers of the eyelid
• Skin and subcutaneous tissue
• Muscular layer
• Submuscular areolar tissue
• Fibrous layer
• Levator apparatus
• Conjunctiva
 Skin
Thinnest in the body, elastic
 Subcutaneous tissue
• Loose connective tissue but no subcutaneous fat thus readily distended by blood/edema
• Eyelashes are attached here with modified sweat gland c/a ciliary glands of Moll and sebaceous glands c/a glands of Zeis.
 The layer of striated muscle
• Orbicularis muscle -- It closes the eyelids and is supplied by zygomatic branch of the facial nerve
• Levator palpebrae superioris muscle (LPS) raises the upper lid. It is supplied by a branch of oculomotor nerve
Orbicularis Muscle
Levator
Palpebrae
Superioris

12.  Submuscular areolar tissue- It is a layer of loose connective tissue. The nerves and vessels lie in this layer. Therefore, to
anaesthetize lids, injection is given in this plane
 Fibrous layer-2 parts the central tarsal plate and the peripheral septum orbitale
 Tarsal Plate- composed of dense connective tissue that give shape and firmness to the lids (skeleton of eyelids). Contains
Meibomian glands (specialised type of sebaceous gland that secretes an oily substance onto the eye to slow the evaporation of
the eye’s tear film. The oily substance also prevents the eyelids from sticking together when closed)
Tarsal Plate
 Layer of non-striated muscle fibers- palpebral muscle of Muller (superior tarsal muscle)
and is supplied by sympathetic fibres of cervical ganglion.
 Conjunctiva fine, translucent mucous membrane that joins and covers the anterior surface
of eyeball and posterior side of the eyelids

13. GLANDS OF EYELIDS
Blood Supply
Ophthalmic, facial, superficial temporal artery
Medially blood drains into ophthalmic vein and laterally into superficial temporal vein
Nerve supply
Sensory information is taken from eyelids by branches of trigeminal nerve i.e. Upper lid by Ophthalmic nerve
Lower lid by Maxillary nerve while muscles are supplied by Facial nerve (orbicularis oculi) and oculomotor nerve (levator
palpebrae superioris) and sympathetic fibres (superior tarsal muscle)
Gland Location Type Opening
Meibomian glands Tarsal plate Sebaceous gland lid margin
Glands of Zeis Subcutaneous tissue Sebaceous gland follicles of eyelashes
Glands of Moll Subcutaneous tissue Sweat glands hair follicles
Wolfring gland Tarsal plate

14. Conjunctiva
Fine, translucent mucous membrane that joins and covers the anterior surface of eyeball (white part-sclera) and posterior
side of the eyelids
2 parts
Palpebral and Bulbar conjunctiva adjoins by Forniceal conjunctiva
Palpebral conjunctiva (3 parts- Orbital, tarsal marginal)
• Covering the lids
• Firmly adherent
• Highly vascular
Bulbar conjunctiva (2 parts- scleral and limbal)
• Covering the eyeball
• Thin, translucent
• Loosely attached
Forniceal conjunctiva
Orbital
Tarsal
Marginal
Scleral
Limbal

15. Layers of conjunctiva
• Epithelium
• Adenoid layer (Lymphoid layer, not present at birth, develops after 2-3 months of life)
• Fibrous layer (collagen + elastic fibres, possess conjunctival vessels and nerves)
Conjunctiva No. of layers
Marginal 5; non-keratinized stratified squamous epithelium
Tarsal 2; stratified cuboidal epithelium
Orbital 2; stratified cuboidal epithelium
Scleral 3; non-keratinized stratified squamous epithelium
Limbal 10; non-keratinized stratified squamous epithelium

16. Conjunctival Glands
• Mucin glands includes goblet cells, Henle’s gland, Gland of Manz
• Accessory Lacrimal gland includes Glands of Krause, glands of Wolfring, Rudimentary ALG
• Goblet cells – oval, absent in marginal and limbal, numerus on nasal side
• Henle’s Gland- tubular structure which contains few goblets cells are present on palpebral conjunctiva
• Gland of Manz – located in bulbar conjunctiva around the cornea
• Glands of Krause- present in upper and lower fornices
• Glands of Wolfrings- situated in the upper part of Tarsal plate

17. Lacrimal Apparatus
• Set of connected anatomical structures located within the orbit that are responsible for the production and drainage of
tears
• Functions 6wks after birth so no tears in new
born when crying
• Divided into 2 parts
 Orbital part
 Palpebral part
• The lacrimal apparatus includes :
 Lacrimal gland
 Lacrimal Puncta
 Lacrimal canaliculi
 Lacrimal sac
 Nasolacrimal duct

18. Lacrimal gland
• Tear-producing organ
• Size of an almond
• Sits within the lacrimal fossa
• Located in the superior and outer edge of the orbital roof
Lacrimal gland
Lacrimal Canaliculi
Lacrimal Sac
Nasolacrimal gland