Vol 11-R2- Eyelid

SRPS • Volume 11 • Issue R2 • 2010
movement of the canthal angle by its posterior
fibrous attachments to the check ligament of the
lateral rectus muscle. In contrast to the medial
canthus, the lateral canthus is mobile, possessing
up to 6 mm of vertical movement and 2 mm of
lateral movement. 28,29 The lateral canthal tendon is
a fibrous structure that joins the upper and lower
tarsal plates to Whitnall tubercle inside the orbital
rim, deep to the septum. Whitnall tubercle is an
area that is not easily found intraoperatively and
must be estimated clinically. It forms a prominence
approximately 5 mm posterior to the lateral orbital
rim. 30 Rosenstein et al. 31 described the lateral
canthal tendon:
“Superiorly, it is in continuity
with the lateral horn of the levator
aponeurosis. Inferiorly, it receives
fibrous contributions from Lockwood’s
suspensory ligament and then curves
posteriorly to attach to Whitnall’s
tubercle. Anteriorly, the lateral extensions
of the preseptal and pretarsal orbicularis
oculi muscles coalesce. Posteriorly,
contributions from the check ligaments
of the lateral rectus muscle complete the
formation of the lateral canthal tendon.”
The lateral canthus is located approximately 2 mm
higher than the medial canthus. The measurement
is the same for both sexes and does not change with
increasing age. 28,32
Vascular Supply of the Eyelids
The eyelids receive their vascular supply from the
facial system, which is made from the branches off
the internal and external carotid arteries. Off of the
internal carotid artery comes the ophthalmic artery,
which branches into the supraorbital, supratrochlear,
dorsal nasal, and lacrimal arteries. The external
carotid artery contributes the facial artery (angular
artery) and superficial temporal artery (transverse
facial artery, median temporal artery, and frontal
and parietal branches). The arterial network of the
upper eyelid is composed of anastomoses between
the collateral branches of the ophthalmic artery
(supraorbital artery, supratrochlear artery, and dorsal
8
nasal artery), a branch of the facial artery (angular
artery), and the superficial temporal artery. 33,34
The lateral region of the upper eyelid also receives
further blood supply from the branches of the
superficial temporal artery and the lacrimal artery. 34
Erdogmus and Govsa 33 described the
connection of the vascular supply and its location:
“The dissection showed that the main
blood supplies of the upper and lower
lids were provided by the arterial arcades;
the marginal, peripheral, superficial,
and the deep ones. The marginal and
peripheral arcades consisted of the
anastomosis of medial and lateral
palpebral arteries. The marginal arcade
coursed just anterior to the lower
margin of the tarsal plate and gave
off small perforating branches that
ascended tortuously on both sides of the
orbicularis oculi muscle and the tarsal
plate. These branches extend to the skin,
the muscle and the tarsal plate. The
perforating branches running over the
orbicularis oculi traversed obliquely, in
contrast to the perforating vessels, with a
descending diameter and became part of
the vascular plexus and lower palpebrae
in all cases. The peripheral arcade coursed
along the upper border of the tarsal plate.
It was positioned along the surface of
the Muller muscle at the superior border
of the tarsus. The peripheral arcade gave
off perforating branches that descended
on both sides of the tarsal plate. The
descending branches running over the
tarsal plate connected with the ascending
branches arising from the marginal
arcade, whereas the descending branches
coursing under the tarsal plate fanned
out fine vessels and formed a vascular
network with the ascending branches
arising from the marginal arcade.”
The authors observed arterial arcades near the
orbital rim and perforating vessels running on the
superficial and deep surfaces of the orbicularis oculi