Orbit presentation for medicine college the second stage

about orbit

1. Nivevalt University

gist dea

Abdulrahman salah

Abdullah amer
his Lay
nik
Ninevah University
ss
Supervisor

Dr. Walid

2. The Orbit
The orbit is a pyramidal shaped cavity
within the skull contains the eyeball
and its associated structures.
Optic nerve

Orbital Contents:

1. Eye ball.

2. Extra ocular muscles.

3. Nerves.

4. Vessels.

5. Orbital Fascia.

6. Fat.

7. Most of the lacrimal apparatus.
+ With the optic nerve as its stem.
- Volume: 30 cc

3. BONY ORBIT
Bany Orbit
Is Four-sided pyramid with its apex directed
posteriorly and base directed Forward to
the face.
It has 4 walls: sup., Inf., med., and lat.
The orbital aperture is not circular in shape,
it is mostly rectangular in shape.
Boundary of Orbital aperture:
1. Superiorly: By Frontal bone which extend
to form part of medial and lateral margin.
2. Lateral margin: Frontal bone and
zygomatic bone.
3. Inferior margin: Zygomatic bone and
maxillary bone.
4. Medial margin: Maxillary and Frontal
bone.

Bones ofthe right bit

4. The Walls of the Orbit:

The medial walls of the orbit is parallel to each other, while the lateral
walls form an angle of about 900 with each other.

Medial wall

Orbital Apex

5. Seven bones of skull share in formation of bony
orbit:

1 — Roof:

* Orbital Plate of frontal bone.

* Lesser wing of sphenoid bone.

2 - Floor:

* Orbital surface of maxilla.

* Zygomatic bone.

* Orbital process of palatine bone.
3 - Medial wall:

* Lacrimal bone.

* Orbital plate of ethmoid bone. * Body of
Sphenoid bone.

4 — Lateral wall:

* Zygomatic bone.

* Greater wing of Sphenoid bone.

6. Muscles of the orbit :

We have extra ocular muscles and intra ocular muscles.
Intra ocular muscles are smooth muscles:

1. Dilator pupillae.

2. Sphincter pupillae. 3. Ciliary muscle.

Extra ocular muscles are skeletal muscles:
1. Levator palpebrae superioris.

2. Sup. rectus. Levator palpebrae superior
3. Inf. rectus. Superior oblique
[| 4. Lat. rectus. Superior

5. Med rectus.
6. Sup. Oblique. _…
Vv’ Inf. Oblique. bone.

x

Lateral

= Inforior rectus.

Medial rectus Inferior oblique

7. Muscle
1- Superior
rectus m.

2- Inferior
rectus m.

3- medial rectus

4- lateral rectus

Origin Insertion NerveSupply Action

Common Into Selera of
tendinous ring eyeball anterior to
which Surrounds equator about
optic canal 6mm from
Superiony, comeoscleral
‘medially and junction

inferiorly

Common Into Sclera of
tendinous ring eyeballanterior to
which Surrounds equator about
optic canal 6mm from
‘Superiorly, comeoscieral
medially and junction

inferiorly

Common Into Selera of
tendinous ring eyeballanterior to
which Surrounds equator about
optic canal 6mm from
‘Superiorly, comeoscleral
medially and junction

inferiorly

Common tendinous Into Sciera of
ring which Surrounds eyeball anterior to
optic canal ‘equator about 6mm,
Superiony, medially from comeoscleral
and inferiorly junction

‘Oculomotor a.

‘Oculomotor n.

Oculomotor n.

Abducent n.

Move the eyeball
upward and
medially

Move the eyeball
downward and
medially

Move the eyeball
medially

Move the eyeball
laterally

8. 5- Levator
palpebrae

superioris

6- Superior
oblique

7- Inferior
oblique

From sphenoid bone Anterior surface

just above optic
canal

From sphenoid
bone above optic
canal then it enters
through trochlea:
Fibro —
cartilaginous ring
attached to orbital
plate of frontal
bone

Orbital plate of
maxillary bone

and upper margin
of superior tarsal
plate of eyelid
Into sclera behind
equator

Into sclera behind
equator

Oculomotor n.

Trochlear n.

Oculomotor n.

Raises upper
eyelid

Move eyeball
downward and
laterally

Move eyeball
upward and
laterally

9. Elevation

Action of Extraocular Muscles

Abduction | Inferior oblique

Elevation

Superior rectus | adduction

Eh Intorsion
Lateral rectus Medial rectus
Depression + > Depression

‘Superior oblique Inferior rectus | Adduction
Abduction Extonsion
Intorsion

10. Lacrimal apparatus:
Consist of lacrimal gland and the drainage system.

Lacrimal sac

Lacrimat
"ake

Lacrimal gland

Nasolrima
“et

> It is an oval shape gland, located in the
superolateral aspect of the orbit, it is about 2cm in
length. It has about 6-12 ducts open to the superior

excretory lariat

fornix (angle between the eyelid and eye ball). ducts <=

>The lacrmal gland consist of two portions separated
by the expanding portion of the aponeurosis of
levator palpebrae superioris

acim vessels
‘nd nerve

Orbital par of.

lacrimal land
Orbital septum

These two parts are: pobre spears
1. Large orbital part superiorly. 2. Small palpebral Popetmlpanos
fami acral
part inferiorly. Escretor duct of —
lacsimal land

11. Nerve supply of lacrimal gland
1. Sensory: lacrimal nerve. p À. A
2. Sympathetic: perivascular plexus around the internal carotid
art. Called (deep

petrosal n).

3. Parasympathetic from zygomatic branch of maxillary nerve
through the

lacrimal nerve.

Creedence ts ct

12. Drainage system

There is a “lacrimal lake ‘in the medial angle of the eye, it is bounded
laterally by a fold of conjunctiva called “plica semilunaris”.

In the lacrimal lake there is an elevated area called “lacrimal caruncle”
formed of non-keratinized skin, it contains sweat and sebaceous glands.
Above and below the lacrimal caruncle there are elevated areas called
“superior and inferior papilla”. In the tip of each papilla, it is an open called
superior and inferior punctum.

The superior and inferior puncta lead to lacrimal canaliculi (sup. And inf.)
which drain the lacrimal secretion into the lacrimal sac, and this sac lead to
nasolacrimal duct which open into the inferior nasal meatus.

This opening is protected by a fold of mucous membrane (like valve) called
lacrimal fold, which prevents return the secretion of nose to orbit.

13. Lymphatic drainage of lacrimal gland

Into anterior auricular group lympH nodes

Excretory ducts of lacrimal gland
Orbital part of lacrimal gland

Lactimal caruncle Lacrimalfold Palpebralfissure

Palpebral part of
lacrimal gland

Lacrimal canaliculi

Lactimal papilla Lacrimalpunctum

Lacrimal papilla and punctum of left eye Lacrimal apparatus