This document summarizes a seminar on the vascular supply and drainage of the orbit. It describes the key arteries supplying the orbit, including the ophthalmic artery and its branches, which provide blood to the eye muscles, lacrimal gland, retina and other orbital structures. It also discusses the venous drainage pathways, with the two ophthalmic veins and angular vein draining into the cavernous sinus and facial veins respectively. Clinical implications of diseases affecting these arterial and venous structures are presented.

1. SEMINAR ON VASCULAR SUPPLY
AND DRAINAGE OF THE ORBIT
Presenter- Dr. Samuael G.(Ophta. R1)
Moderator- Dr. Haftamu A.(Ophthalmologist)
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2. CONTENTS;
Arterial supply of the orbit
Venous drainage of the orbit
Cavernous sinus and its clinical significance
Lymphatic drainage of the orbit
REFERENCE
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3. Arterial Supply of the Orbit
 The arteries of the orbit correspond
essentially to the ophthalmic artery and its
branches;
 The orbit is also supplied by the infraorbital
artery, a branch of the maxillary artery which
is itself the terminal branch of the external
carotid artery.
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4.  The internal carotid
arteries arise in the neck
from the common carotid
arteries . The cervical part
of each artery ascends
vertically through the
neck, without branching,
to the cranial base. Each
internal carotid artery
enters the cranial cavity
through the carotid canal
in the petrous part of the
temporal bone
Common ca A.
Origin of
Ophthalmic A.
Internal Carotid A.
Carotid canal
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5. 5/4/2020 5
Cerebral part of internal
carotid artery (will join
cerebral arterial circle
Cavernous part of
internal carotid artery
in cavernous sinus
Petrous part of
internal carotid artery
in carotid canal
Cervical part of
internal carotid artery
and sympathetic plexus

6.  CLINICAL COMMENT: SCLEROSIS OF THE
INTERNAL CAROTID ARTERY
 Compression of the optic nerve caused by sclerosis of
the internal carotid artery was found, with pathologic
changes such as atrophy, evident in the optic nerve.
Visual field defects may be caused by this
compression and should be one of the differential
diagnoses when optic nerve head atrophy
accompanies a field defect.
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7.  The ophthalmic artery,
 Diameter of 1.5 mm,
 Arising anteriorly where it emerges from the
cavernous sinus medial to the anterior clinoid
process.
 Makes its way through the subarachnoid
space below the optic nerve and then
continues on into the optic canal, carrying on
laterally to perforate the sheath at the exit of
the canal.(Infero-laterally)
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8. 5/4/2020 8

9.  In the orbital cavity,
 Initially lateral to the optic nerve and medial
to the ciliary ganglion.
Next, obliquely and accompanied by the
nasociliary nerve, it crosses the top side of the
optic nerve below the superior rectus muscle,
ultimately reaching the medial orbital wall.
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11.  From there it makes its way forward between
the superior oblique and the medial rectus
muscles, passes under the trochlea and then
climbs back up again to pass between the
orbital rim and the medial palpebral ligament.
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13.  It terminates by splitting into two different
arteries, the supratrochlear artery and the
angular artery (which forms an anastomosis
with the dorsal artery of the nose).
 It should be noted that in about 15% of
subjects, the ophthalmic artery passes
underneath optic nerve.
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14.  ICA Internal carotid artery,
 OphA ophthalmic artery,
 SOV superior ophthalmic vein,
 PEA posterior ethmoidal artery,
 AEA anterior ethmoidal artery,,
 SOA supra orbital artery,
 STA supra trochlear artery,
 DNA dorsal nasal artery,
 MusA muscle artery
 LA lacrymal artery
 LPCA long posterior ciliary artery
 CAR
 SPCA
Fig.1, superior view of right orbit showing ophthalmic
artery and its branches5/4/2020 14

15. Collateral branches of the ophthalmic artery;
 Variable in number from 10 to 19,
most of these arise in the intraorbital
segment of the artery.
Anatomical variations are very common.
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16. 5/4/2020 16

17. 1. The central artery of the
retina —one of the
smallest—is present in
all cases. It arises from
the ophthalmic artery in
50% of subjects, and
from one of its branches
(the posterior long
ciliary artery) in the
other 50%.
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18.  It often arises below and outside the optic
nerve and then skirts over its lower side
before penetrating at a distance of 10–15 mm
from the posterior pole of the eyeball. It then
continues as far as the papilla where it splits
to form its terminal branches.
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19. 5/4/2020 19

20. 5/4/2020 20

21.  Supply -the retina except the fovea(choroid)
-the optic nerve(visual path way)
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22.  CLINICAL COMMENT: RETINAL VENOUS BRANCH
OCCLUSION
 The branches of the central retinal artery and vein are
joined in a common connective tissue sheath.
 The artery crosses over the vein and, in such disease
processes as arteriosclerosis, may compress the vein at
the crossing, causing at first a deflection of the vessel,
which in time may progress to a venous occlusion.
Restriction of flow in the vein results in retinal edema
and hemorrhage in the area surrounding the occlusion.
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23.  CAR is an end artery like the arteries of the
brain because from an embryologic point of
view the retina is a part of the brain. It has a
dual supply like the brain, the outer one-third
by choriocapillaris and the inner two-thirds by
branches of the CRA.
 Since it is an end artery, its occlusion will
result in a total loss of vision.
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24. 2. The lacrimal artery, one of
the largest branches, arises
near the exit of the optic
canal above and outside
the optic nerve. It passes
forwards, upwards and in a
lateral direction, coming
out of the cone to continue
to the lateral wall of the
orbit where it carries on
with the lacrimal nerve
above the lateral rectus
muscle as far as the
lacrimal gland.
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25. 5/4/2020 25

26. This artery gives rise to one or two zygomatic
branches. One of these passes across the
zygomatico-temporal foramen and forms an
anastomosis with the deep temporal arteries.
The lacrimal artery gives a recurrent
anastomotic branch that passes through the
lateral part of the superior orbital fissure to
rejoin a branch of the middle meningeal
artery.
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27. 5/4/2020 27

28.  Supply –the lacrimal gland and the upper eye
lid.(lateral palpebrar aa.)
- May supply branches to lateral rectus
muscle
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29. 3, Muscular branches; are numerous.
 These often arise from one or two arterial
trunks.
The inferior muscular artery—one of the
largest of the branches of the ophthalmic
artery—is the most commonly found. Other
muscular branches exist, arising in the
ophthalmic artery or one of its branches.
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31. • lateral (or superior) - branch supplies the
lateral rectus, superior rectus, superior
oblique and levator muscle
• the medial (or inferior)- supplies medial
rectus, inf. Rectus and inf. Oblique muscle
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32. 4, The ciliary arteries ; can be divided into three
different groups:
The posterior long ciliary arteries, commonly
two in number, arise in the ophthalmic artery
at the point at which it crosses over the optic
nerve.
• These enter the sclera not far from where the
optic nerve enters it.
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34.  The posterior short ciliary arteries; seven in
number, pass in a forward direction around the
optic nerve. 10-20 branches
• They enter the sclera in a ring around the optic
nerve and form the arterial network within the
choroidal stroma . Other branches from the short
posterior ciliary arteries anastomose to form the
circle of Zinn (Zinn-Haller) which encircles the
optic nerve at the level of the choroid.
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36.  The anterior ciliary arteries; arise from
muscular branches and pass in front, over the
tendons of the rectus muscles.
 These arteries anastomose to form the
greater arterial circle of the iris.(sends
branches posteriorly into ciliary body as well
as forward into iris )
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37. 5, The supraorbital artery; (which is absent in 12%
of subjects)
Arises from the ophthalmic artery, often in its
medio-optic part.
It passes up and forwards, comes out of the cone
between the levator palpebrae superior muscle
and the superior oblique muscle, and then meets
the supraorbital nerve, which it accompanies
between the levator muscle and the periorbita
until the supraorbital incisure or foramen.
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38. Inside the orbit, it gives rise to muscular
branches (s.rectus, s.oblique, levator mus.)
and, in some cases, the supratrochlear artery.
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39. • 6, The posterior ethmoidal artery; arises within
the muscular cone medial and above the optic
nerve then leaves the cone between the superior
oblique muscle underneath and the levator
muscle above to carry on over the trochlear
nerve towards the posterior ethmoid canal.
• Supply the posterior ethmoid sinus and the
sphenoid sinus; it sends branches into the nasal
cavity to supply the upper part of the nasal
mucosa..
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41. • 7, The anterior ethmoidal artery, which is
present more often than the preceding vessel,
arises near the anterior ethmoid canal: when
it enters this canal, it is accompanied by the
nerve of the same name.
• Supplies the anterior and middle ethmoid
sinuses, the sphenoid sinus, the frontal sinus,
the nasal cavity, and the skin of the nose
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42. 8, The meningeal branch; is a small branch that
passes behind, across the superior orbital
fissure, into the middle cerebral fossa to form
an anastomosis with the middle and accessory
meningeal arteries.
9, The medial palpebral arteries, two in number
(the superior and the inferior), arise from the
ophthalmic artery below the trochlea.
@ SUPPLY BOTH EYE LIDS.
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43. 5/4/2020 43

44. 10, The supratrochlear artery, a terminal branch
of the ophthalmic artery, leaves the orbit in
the superomedial part together with the
nerve of the same name.
11, The dorsal artery of the nose, another
terminal branch of the ophthalmic artery,
emerges from the orbit between the trochlea
and the medial palpebral ligament.
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45. Venous Drainage of the Orbit
 There is a very dense
venous network in the
orbit, organized around
the two ophthalmic
veins that drain into the
cavernous sinus.
These veins are valve-
less.
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46.  Periorbital drainage also occurs towards the
facial system via the angular vein. Thus, for
the venous system, as with the arterial
system, the orbit is a site of anastomosis
between the endocranial and exocranial
systems.
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47. 5/4/2020 47

48. 5/4/2020 48

49.  The superior
ophthalmic vein,
 A large-caliber vein
present in all subjects,
 It is formed by the
union behind the
trochlea of two rami,
the first from the
frontal veins and the
other from the angular
vein.
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50. superior ophth..
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51. superior ophth..
• This vessel then crosses
the orbit from the front
towards the back
accompanying the
artery and passing
under the superior
rectus muscle.
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52. superior ophth..
 The veins that drain into the superior
ophthalmic vein are the anterior and posterior
ethmoid veins, the muscular veins draining
the superior and medial muscles, the lacrimal
vein, the central retinal vein, and the upper
vortex veins.
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53. superior ophth..
 It passes below the superior rectus muscle
and crosses the optic nerve to the upper part
of the superior orbital fissure, where it leaves
the orbit to empty into the cavernous sinus.
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54. superior ophth..
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55.  The inferior ophthalmic
vein ,
 that is not present in all
subjects, is the result of
a venous anastomosis
in the anterior
inferomedial part of the
orbit.
 It receives rami from
muscles, the lacrimal
sac and the eyelids.
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56. inferior op…
• It carries on behind, above the inferior rectus
muscle, whence it often rejoins the superior
ophthalmic vein, although in some subjects, it
carries on to the cavernous sinus as a distinct
vessel.
• It communicates with the pterygoid plexus by
small veins crossing the walls of the orbit.
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57. inferior op…
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58. CENTRAL RETINAL VEIN
 The venous branches located in the retinal
tissue come together and exit the eyeball as a
single central retinal vein.
 This vessel leaves the optic nerve
approximately 10 to 12 mm behind the lamina
cribrosa alongside the central retinal artery.
 It leaves optic nerve and either joins the
superior ophthalmic vein or exits the orbit
and drains directly into the cavernous sinus.
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59.  CLINICAL COMMENT: PAPILLEDEMA???
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60. Vortex vein
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61. Vorte…
 The vortex veins drain the choroid, and
usually one of the four or five vortex veins is
located in each quadrant.
 Exit the globe 6 mm posterior to the equator.
 The vortex veins can be seen with an indirect
ophthalmoscope and a dilated pupil.
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62. Vorte…
 Anterior and posterior uvea drains through
vortex veins then to____ superior and inferior
orbital veins to____ cavernous sinus.
 Eyelids drain through facial vein and angular
veins.
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63. ANTERIOR CILIARY VEINS
 The anterior ciliary veins receive branches
from the conjunctival capillary network and
then accompany the anterior ciliary arteries,
pierce the sclera, and join with the muscular
veins
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64. Infraorbital vein
 The infraorbital vein is formed by several
veins that drain the face..
 It receives branches from some structures in
the inferior part of the orbit and may
communicate with the inferior ophthalmic
vein.
The infraorbital vein drains into the pterygoid
venous plexus.
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65. 5/4/2020 65

66. Cavernous sinus
 The CS are venous
structures in the middle
cranial base, directly
behind the SOF.
surrounded by dural
walls,
 contain neurovascular
structures.
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67. Cavernous…
 Covers the lateral aspects of the
sphenoid body with a height of
about 1 cm and a length of about
2 cm
 Serves as a conduit for most of
the neurovascular supply the
orbit
 The sinus receives venous blood
from the superior ophthalmic
vein
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68. Relations/Communications
 Above- optic chiasma,
carotid siphon
 Below- sphenoid sinus
 Medial- hypophysis
cerebri
 Lateral- posterolateral
part of trigeminal
ganglion
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69. Cavernous…
 A cavernous sinus has five walls:
 The roof faces the basal cisterns;
 The lateral wall faces the temporal lobe;
 The medial wall faces the sella turcica, pituitary
gland, and sphenoid bone;
The posterior wall faces the posterior cranial
fossa, and
The narrow anterior edge borders the superior
orbital fissure
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70. Cavernous…
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71. Cavernous…
 The medial and lateral walls join inferiorly at
the level of the superior margin of the second
division of the trigeminal nerve (maxillary
nerve).
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72. Structures passing through CS
 ICA surrounded by veins and
sympathetic plexus
 Abducent nerve- inferior and
lateral to carotid A.
 Occulomotor nerve
 Trochlear n.
 Ophthalmic n.
 Maxilary n.
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73. Cavernous…
 The cavernous sinus drains into the superior
petrosal sinus, and inferior petrosal sinus.
 Both drain either directly or indirectly into
the internal jugular vein.
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74. Clinical significance!!!!
 Infections of the face or orbit can be dangerous
 An infected embolus that forms in a facial or orbital
vein can directly pass into the cavernous sinus via an
ophthalmic vein(??veins are valve less)
 CVT must be treated promptly
 Carotid–cavernous sinus fistula
– Abnormal communication b/n CA & CS
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75. Lymphatic Drainage of the orbit
 No lymphatic vessels
occur in the globe
proper;
 Lymphatics are found in
the conjunctiva and the
eyelids.
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76. Lymphatic Drai…
 Most of the upper eye lid, lateral third of the
lower eyelid, and lateral canthus drain into the
pre auricular and deep parotid nodes.
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77. Lymphatic Drai…
 The medial portion of the upper eyelids, the
medial canthus and the medial two thirds of
the lower lid and conjunctiva drain into the
sub mandibular nodes.
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78. Lymphatic Drai…
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79. EFFECT OF AGING ON
OCULAR CIRCULATION
 The density and diameter of the
choriocapillaris decrease with age.
Because there is a coincident decrease in
retinal cells, this decrease in blood flow may
be a response to decreased metabolic need.
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80. Reference
• Moore, 7th edition
• Atlas of the ocular system
• Anatomy of the visual system
• Duan's Ophthalmology
• BCSC 2018/19
• NETTER ATLAS OF HUMAN ANATOMY
SEVENTH EDITION 2019
• Internet…..
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