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How much eyelid skin should remain between the eyelid margin and the start of the brow.
20 mm, to avoid lagophthalmos
How do you locate the lateral orbital tubercle (Whitnall's tubercle)?
10 mm below the zygomaticofrontal suture and 4 mm behind the anterior lateral orbital rim. The lateral canthal tendon, Whitnall's ligament, and Lockwood's ligament attach here.
What are the average distances of the anterior ethmoid foramen, posterior ethmoid foramen, and optic foramen from the lacrimal crest
average distance from the anterior lacrimal crest to the anterior ethmoid foramen is 24 mm, to the posterior ethmoid foramen is 36 mm, and to the optic foramen is 42 mm.
What structures pass through the optic foramen, superior orbital fissure, and inferior orbital fissure?
- The optic foramen, within the lesser wing of the sphenoid, transmits the optic nerve, ophthalmic artery, and sympathetic fibers
- The superior orbital fissure transmits cranial nerve IV, ophthalmic and mandibular divisions of cranial nerve V, cranial nerve VI, the nasociliary nerve, the superior and inferior ophthalmic veins, the lacrimal nerve, and the frontal nerve.
- Inferior orbital fissure posteriorly transmits the sphenopalatine ganglion, and the maxillary division of the trigeminal nerve.
The SMAS s contiguous with which structures superiorly and inferiorly?
The platysma and temporoparietal fascia.
Which muscles are responsible for forehead rhytids?
- Frontalis (horizontal rhytids): inserts into the skin of the eyebrow. Continuation of then galea aponeurotica from the coronal suture downward, and inserts in the dermis.
- Procerus (horizontal rhytids): frontalis muscle extends to form the procerus muscle. Procerus originates on the caudal aspect of the nasal bones and cephalic margins of the upper lateral cartilages.
- Corrugator supercilii (vertical rhytids): originates from the nasal process of the frontal bone,inserts into the dermis at the middle third of the eyebrow
What structures form the upper eyelid crease?
upper lid crease is the line formed by the insertion of the levator aponeurosis and orbital septum into the orbicularis oculi muscle and skin.
How far from the lid margin should the upper lid crease be?
In women, the lid crease is 10 to 12 mm above the lid marginin men it is 7 to 8 mm above the lid margin.
What is the anatomic difference between the Asian and Caucasian upper eyelid?
In the Asian eyelid, the orbital septum and levator aponeurosis attach to the skin further inferiorly, anterior to the tarsus. As a result, orbital fat prolapses anteriorly, thereby preventing the formation of a prominent upper eyelid crease
What is the role of each of the three parts of the orbicularis oculi?
- Blinking is an involuntary action that depends on contraction of the pretarsal orbicularis (innermost).
- The preseptal fibers contribute to both the involuntary and voluntary functions of the eyelids.
- Winking is a voluntary action dependent upon the orbital orbicularis (outermost).
Describe the location of the lower lid fat pads.
The lower eyelid contains three fat pads: medial, central, and lateral. The medial and central fat pads are separated by the inferior oblique muscle
What is the size of the upper and lower tarsal plate?
upper eyelid tarsal plate is 10 to 12 mm in vertical height while the lower eyelid tarsal plate is 3 to 5 mm in vertical height
Describe the classic brow position.
- In women, the medial brow begins at the level of a vertical line drawn to the nasal alar-facial junction. The lateral extent should reach a point on a line drawn from the nasal alar-facial junction through the lateral.
- Classically, the arch should be at the lateral limbus, but more recently it's described as lying at the lateral canthus.
How do you evaluate the integrity of eyelid skin?
- The pinch test helps determine the degree of excess lid skin that is present.
- The snap test helps determine the degree of lower lid laxity and is useful in preoperative planning. It is performed by retracting lid inferiorly with one fingerand observing its ability to snap back. A normal lid will return to its position immediately.
In the aging patient, what produces the flattened malar eminence?
Descent of the subcutaneous malar fat pads, as well as the suborbicularis oculi fat (SOOF), results in a flattened malar eminence and prominent orbital rims.
During a blepharoplasty, how much orbital fat should be removed?
After opening the septum, only fat that protrudes into the wound with gentle globe pressure should be clamped and excised to avoid overaggressive removal of orbital fat.
How would you manage post-op lagophthalmos?
- Edema can cause lagophthalomos, and conservative measures are appropriate, including eye care precautions to prevent corneal exposure complications.
- If lagophthalmos persists beyond 6 to 8 postoperative weeks, an excess of upper eyelid skin may have been removed at the time of surgery, a skin graft may be necessary to replace the missing skin.
Which Norwood classification is depicted?
- V or VI