orbit anatomy along with its borders and contents. extra ocular muscles and their attachment , and their actions, along with their innervation. strabismus and squint. damage of occulomotor, trochlear and abducent nerve sign and symptoms of the patient.

1. ORBIT &
EXTRAOCULAR
MUSCLE
DR SANA YASEEN
ANATOMY DEPARTMENT

3. INTRODUCTION
 Bony cavities lodging eyeball, muscle, vessels and
lacrimal gland
 Bilateral structure present in upper ½ of face below
ant cranial fossa and ant to middle cranial fossa.
 Its framework is composed of 7 bones;

6. OPENINGS IN ORBITAL CAVITY
 Orbital opening: anteriorly, 1/6 of eye is exposed.
Remainder is protected by the wall of the orbit.
 Supra orbital notch (foramen): situated on the superior
orbital margin. It transmits supra orbital nerve and
vessels
 Infra orbital groove and canal: floor of orbital in the
orbital plate of maxilla. Transmit infra orbital nerve (br of
maxillary) and vessels
 Nasolacrimal canal: located anteriorly on the medial
wall, it communicates with the inferior meatus of the
nose. It transmit nasolacrimal duct

7. Infra orbital
foramen
Nasolacrimal canal
superior orbital fissure
Optic canal
Inferior orbital fissure
Supra orbital notch
(foramen)

8.  Inferior orbital fissure: located posteriorly between greater
wing of sphenoid and maxilla. It communicates with
pterygopalatine fossa. It transmits maxillary nerve and its
Zygomatic branch , inferior ophthalmic vein and sympathetic
nerves.
 superior orbital fissure. Located posteriorly between
greater and lesser wing of sphenoid. Communicates with
pterygopalatine fossa. It communicates with middle cranial
fossa. It transmits 3rd, 4th nerve, nasolacrimal nerve and
superior ophthalmic vein
 Optic canal: posteriorly present in lesser wing of sphenoid.
Communicates with middle cranial fossa. Transmits optic
nerve and ophthalmic artery.

10. ORBITAL FASCIA
 Forms wall of orbit
 Loosely attach to bones
and is continuous
through foramina and
fissures with periosteum
covering the outer
surface of the bones.
 The muscle of Muller, or
orbitalis muscle, is a thin
layer of smooth muscle
that bridges the inferior
orbital fissure.
 It is innervated by
sympathetic nerve ,
function unknow.

11. ORBITAL CONTENTS

12. CONTENTS
 EYE BALLS
 FASCIA: orbital & bulbar
 MUSCLES: extra ocular muscles
 VESSELS: ophthalmic artery, superior inferior
ophthalmic vein, lymphatics
 NERVE: optic, occulomotor, trochlear, abducent, br
of ophthalmic and maxillary , sympathetic nerves
 LACRIMAL GLANDS
 ORBITAL FATS

13. EXTRA OCULLAR MUSCLES

14.  There are 6 muscles resposible for eye movement.
 These muscles are attached to the sclera of the eye
at one end and are anchored to the bony orbit of the
eye at their opposite ends or some have same
common tendonus origin.
 Contraction of the muscles produce movement of
the eyes within the orbit.

15. SUPERIOR RECTUS
INFERIOR OBLIQUE INFERIOR RECTUS
MEDIAL RECTUS
LATERAL RECTUS
SUPERIOR
OBLIQUE

16.  There are four recti (latin; straight); superior,
inferior, medial, and lateral.
 They all share a common origin, a fibrous ring of
connective tissue located posteriorly at the apex of
the orbit, called the tendinous ring or the annulus of
Zinn.
 There are two oblique muscles, the superior and
inferior oblique.
 They do not originate from the common tendinous
ring but rather have bony origins within the orbital
cavity.

17. Ring of fibrous tissue that surrounds the
optic canal

18. Superior rectus
 Origin: the superior aspect of the common tendinous ring
 Insertion: the anterosuperior aspect of the sclera of the eye
 Primary action: elevates the eye (directs the eye upwards)
 Secondary action: assists with medial rotation and adduction
 Innervation: oculomotor nerve (CN III)
Inferior rectus
 Origin: the inferior aspect of the common tendinous ring
 Insertion: the anteroinferior aspect of the sclera of the eye
 Primary action: depresses the eye (directs the eye
downwards)
 Secondary action: assists with lateral rotation and adduction
 Innervation: oculomotor nerve (CN III)

19. Medial rectus
 Origin: the medial aspect of the common tendinous ring
 Insertion: the anteromedial aspect of the sclera of the eye
 Primary action: adducts the eye
 Innervation: oculomotor nerve (CN III)
Lateral rectus
 Origin: the lateral aspect of the common tendinous ring
 Insertion: the anterolateral aspect of the sclera of the eye
 Primary action: abducts the eye
 Innervation: abducens nerve (CN VI)

21. Superior oblique
 Origin: the body of the sphenoid bone (posterior wall of the
orbital cavity)
 Insertion: it travels across the medial edge of the roof of the
orbit and then hooks around the trochlea, a pully-like structure
at the superior-medial corner of the orbital cavity. Then it turns
posteriorly to be inserted into the posterior-lateral quadrant of
the superior surface of the sclera.
 Action: medial rotation, depression and abduction
 Innervation: trochlear nerve (CN IV)
Inferior oblique
 Origin: the inferomedial aspect of the orbital floor
 Insertion: lateral aspect of the inferior surface of the sclera,
posterior to the lateral rectus
 Action: lateral rotation, elevation and abduction
 Innervation: oculomotor nerve (CN III

22. They attach to posterior surface of clera
unlike recti muscles.

25.  the medial rectus and lateral rectus, work together
to control horizontal eye movements.
 Contraction of the medial rectus pulls the eye
towards the nose (adduction or medial movement).
 Contraction of the lateral rectus pulls the eye away
from the nose (abduction or lateral movement).
 The actions of these two muscles are antagonistic:
one muscle must relax while the other contracts to
execute horizontal eye movements.
 Four other extraocular muscles working together
control vertical eye movements and eye rotation
around the mid-orbital axis

27. MOVEMENTS CAUSED BY EXTRAOCULAR
MUSCLES OF AN EYE
Superior rectus muscle
Medial rectus muscle
Inferior rectus
Superior oblique
Inferior oblique
Lateral rectus

29. MUSCLES WITH THEIR MOVEMENTS

30. CARDINAL POSITION OF GAZE

31. Down and out

32. Up and out

33. Down and in

34. Up and in

36. SQUINT/ STRABISMUS
 Weakness/ paralysis of an eye causes
squint/strabismus which may be concomitant/paralytic.
 CONCOMITANT: is congenital, there is no movement
limitation or diplopia
 PARALYTIC: movement are limited, diplopia & vertigo.
Head moves in the direction of function of paralysed
muscle. False orientation of field of vision.
 NYSTAGMUS: is characterized by involuntary
rhythmical oscillation of eye.

37. Clinically testing of the gaze

39. Oculomotor nerve palsy (CN III)
 The oculomotor nerve supplies all extraocular
muscles except the superior oblique (CNIV) and
the lateral rectus (CNVI). Oculomotor palsy (‘third
nerve palsy’), results in the unopposed action of both
the lateral rectus and superior oblique muscles,
which pull the eye inferolaterally.
 patients typically present with a ‘down and out’
appearance of the affected eye.
 Oculomotor nerve palsy can also cause ptosis (due
to a lack of innervation to levator palpebrae
superioris) as well as mydriasis (dilation of pupil)
due to the loss of parasympathetic fibres responsible
for innervating to the sphincter pupillae muscle.

41. Trochlear nerve palsy (CN IV)
 The only muscle the trochlear nerve innervates is the
superior oblique muscle.
 trochlear nerve palsy (‘fourth nerve palsy’) typically
results in vertical diplopia when looking inferiorly, due to
loss of the superior oblique’s action of pulling the eye
downwards. Patients often try to compensate for this by
tilting their head forwards and tucking their chin in, which
minimises vertical diplopia.
 Trochlear nerve palsy also causes torsional diplopia (as
the superior oblique muscle assists with intorsion of the
eye when the head tilts). To compensate for this, patients
with trochlear nerve palsy tilt their head to the opposite
side, in order to fuse the two images.

43. Abducens nerve palsy (CN VI)
 The abducens nerve (CN VI) innervates the lateral
rectus muscle.
 Abducens nerve palsy (‘sixth nerve palsy’) results in
unopposed adduction of the eye (by the medial
rectus muscle), resulting in a convergent squint.
 Patients typically present with horizontal diplopia
which is worsened when they attempt to look
towards the affected side.