[06.20] CMD - Eyelid Disorders V2.2.pdf

Skin, subcutaneous tissue, Superficial Musculoaponeurotic System (SMAS), mimetic muscles, deep facial fascia, and the plane containing the facial nerve, parotid duct, and buccal fat pad

What are the structural planes of the face from superficial to deep?

Superficial Musculoaponeurotic System (SMAS)

Which facial structure distributes facial muscle contractions to facilitate facial expression?

Orbitomalar, zygomatic, and mandibular ligaments

Which ligaments formed by the facial fasciae provide support for facial muscles?

Attenuation of facial supporting ligaments and facial dermal elastosis

What two age-related anatomical changes make facial aging visually apparent?

Dissection, repositioning, and support of the SMAS

What surgical manipulations of the SMAS are critical during facial cosmetic surgery?

Framing the eyes and serving as an indicator of facial expression and mood

What is the primary aesthetic and communicative role of the eyebrow?

Position, composition, and angulation

What three features of the eyebrow contribute to how a person's mood and affect are perceived?

Head

Which anatomic part of the eyebrow starts near the inner corner of the eye?

Body

Which anatomic part of the eyebrow contains the peak of the brow?

Line skirting the inner limbus going to the alae nasi

What landmark line determines the position of the body and peak of the eyebrow?

Tail

Which anatomic part of the eyebrow ends along a line angled toward the alae nasi?

Flat and full

What are the structural shape characteristics of male eyebrows?

On the superior orbital rim

Where do male eyebrows normally sit relative to the bony orbit?

Thin and arched

What are the structural shape characteristics of female eyebrows?

Above the superior orbital rim

Where do female eyebrows sit relative to the bony orbital rim?

Medial to the lateral canthus

Where is the highest point of the arch located in female eyebrows?

It alters eyelid appearance

Why must eyebrow position be evaluated prior to performing any eyelid surgery?

Just nasal to the pupil

Where is the highest peak of the normal upper eyelid contour located?

Slightly below the upper limbus, partially covering it

Where does the normal upper eyelid margin rest relative to the limbus?

Lateral limbus

Where is the lowest point of the lower eyelid contour located?

Directly at the lower limbus

Where does the normal lower eyelid margin rest relative to the limbus?

Lateral canthus

Which canthus is normally positioned slightly higher, the medial or lateral canthus?

30 mm

What is the normal horizontal length of the eyelid?

10 mm

What is the normal vertical height of the palpebral aperture?

Skin of the eyelids

What is the thinnest skin in the entire human body?

Facilitating rapid, uninterrupted blinking

What functional advantage is provided by the extreme thinness of eyelid skin?

Skin and orbicularis oculi muscle

Which structures comprise the anterior lamella of the eyelid?

Tarsus and conjunctiva

Which structures comprise the posterior lamella of the eyelid?

Skin, subcutaneous tissue, muscle of protraction, orbital septum, orbital fat, muscle of retraction, tarsus, and conjunctiva

What are the eight structural layers of the eyelid from superficial to deep?

Contraction of underlying facial and eyelid muscles

What causes the formation of facial rhytids and wrinkles?

Orbicularis oculi

Which protractor muscle is responsible for the formation of crow's feet wrinkles?

Procerus muscle

Which muscle attaches from the frontal bone to the glabella and produces glabellar furrows?

Corrugator muscle

Which muscle attaches from the eyebrow to the nasal bone?

Orbicularis oculi, corrugator muscle, and procerus

What three muscles function as eyelid protractors responsible for upper eyelid closure?

Pre-tarsal, pre-septal, and orbital components

What are the three anatomical subdivisions of the orbicularis oculi muscle?

Levator palpebrae superioris, Müller's muscle, and frontalis muscle

What three muscles function as retractor muscles responsible for upper eyelid opening?

Levator palpebrae superioris

What is the primary elevator muscle of the upper eyelid?

Cranial Nerve III (Oculomotor Nerve)

Which nerve innervates the levator palpebrae superioris for voluntary upper lid elevation?

Whitnall's ligament (Superior transverse ligament)

What fibrous structure represents the extension of the levator muscle beyond the orbital rim?

Anterior surface of the tarsus and overlying skin

Where does the fibrous aponeurosis of the levator muscle insert?

Attachments of the levator aponeurosis to the orbicularis muscle and skin

What anatomical structures form the upper eyelid skin crease?

Separates the upper skin fold from the flat pre-tarsal component

What does the upper eyelid crease separate?

Serves as a good surgical incision site and hides post-operative scars

Why is the upper lid crease of great surgical significance?

6 to 8 mm

What is the normal upper lid crease height in Caucasian men?

Women

Do men or women have a slightly higher upper eyelid skin crease?

Lower levator aponeurosis insertion allowing preaponeurotic fat to descend onto the tarsal plate

What anatomical variation explains why Asian eyelids often appear to have no lid crease and a puffier look?

Müller's muscle (Superior tarsal muscle)

Which non-striated muscle provides involuntary upper eyelid elevation?

Sympathetic nervous system

Which nerve pathway provides innervation to Müller's muscle?

1 to 2 mm

How many millimeters of upper eyelid elevation is contributed by Müller's muscle?

Between the conjunctiva and levator muscle, inserting into the superior tarsal border

Where is Müller's muscle anatomically located?

Peripheral vascular arcade

What vascular landmark located at the superior tarsal border lies between the levator aponeurosis and Müller's muscle?

Capsulopalpebral fascia

Which lower eyelid retractor structure is analogous in function to the levator muscle of the upper lid?

Inferior rectus muscle to the inferior border of the tarsal plate

Where does the capsulopalpebral fascia extend anatomically?

Inferior tarsal muscle

Which lower eyelid retractor muscle is analogous in function to Müller's muscle of the upper lid?

Posterior to the capsulopalpebral fascia

Where is the inferior tarsal muscle situated relative to the capsulopalpebral fascia?

Lockwood's ligament to the inferior tarsal border

Where does the inferior tarsal muscle extend anatomically?

Tarsus (tarsi) or tarsal plate

What dense plates of connective tissue serve as the primary structural support of the eyelids?

10 to 12 mm

What is the vertical height of the tarsal plate in the upper eyelid?

4 to 6 mm

What is the vertical height of the tarsal plate in the lower eyelid?

Medial and lateral canthal tendons (ligaments)

What structures anchor the tarsal plates rigidly to the periosteum of the orbital bones?

Age-related stretching of the canthal tendons

What causes horizontal displacement and laxity of the tarsal plates in older adults?

Orbital septum

What thin, multi-layered fibrous sheet arises from the arcus marginalis along the orbital rims?

Arcus marginalis

What periosteal line at the orbital rim serves as the site of origin for the orbital septum?

Levator aponeurosis in the upper lid and capsulopalpebral fascia in the lower lid

With which retractor structures does the orbital septum fuse?

Attenuation or thinning of the orbital septum

What structural change in the orbital septum allows orbital fat to herniate forward in aging eyelids?

Anterior to the levator muscle and posterior to the orbital septum

Where is preaponeurotic orbital fat located?

Breach of the orbital septum with potential injury to the levator complex and risk of ptosis

What does the presence of orbital fat in an upper lid laceration signify?

Medial (nasal) fat pad and central fat pad

What are the two preaponeurotic fat pads present in the upper eyelid?

Medial (nasal) fat pad

Which upper lid fat pad is characterized by a whiter color and smaller size?

Medial (nasal), central, and lateral (temporal) fat pads

What are the three orbital fat pads present in the lower eyelid?

Inferior oblique muscle

Which extraocular muscle is located specifically between the medial and central fat pads of the lower eyelid?

Suborbicularis oculi fat (SOOF)

What deep subcutaneous fat layer lies beneath the orbicularis oculi muscle and extends from the lower lid to the midface?

SOOF descent, septal thinning, fat prominence, and attenuation of canthal tendons/ligaments

What four anatomical aging changes lead to the appearance of eye bags or dermatochalasis?

Dermatochalasis

What is the medical term for under-eye bags caused by aging changes in the SOOF, septum, and skin?

Eyelid coloboma

What embryologic cleft defect involves a full-thickness notch or absence of the eyelid margin?

Isolated congenital anomaly

What is the significance of an eyelid coloboma located on the medial upper eyelid?

Association with systemic congenital conditions such as Goldenhar syndrome facial clefts or lacrimal deformities

What is the significance of an eyelid coloboma located on the lower eyelid?

Full-thickness defect involving the eyelid margin

What defines a true eyelid coloboma?

Blepharitis

What inflammation of the eyelid margins presents with redness, itching, and dandruff-like scales around the base of the eyelashes?

Collarettes

What name is given to the dandruff-like keratinous scales formed around the base of the eyelashes in blepharitis?

Bacterial colonization or clogged Meibomian oil glands

What are the two primary causes of blepharitis?

Eyelid hygiene using mild shampoo or antibiotic lid scrubs

What is the primary treatment for blepharitis?

Hordeolum (stye)

What acute, painful, localized bacterial infection causes focal eyelid swelling?

Internal hordeolum

Which type of stye results from acute bacterial infection or inflammation of a Meibomian gland?

External hordeolum

Which type of stye results from acute bacterial infection of the Zeiss or Moll glands near the lash follicles?

Warm compresses combined with topical or oral antibiotics

What is the treatment for an acute hordeolum?

Chalazion

What focal, non-tender, chronic lipogranulomatous cyst forms within the eyelid?

Inflammation following blockage of a Meibomian gland duct, or an undertreated stye

What causes the development of a chalazion?

Warm compresses and proper surgical incision and curettage (drainage)

What interventions are required for persistent chalazion removal?

Ectropion

What medical term describes outward turning or eversion of the eyelid margin?

Medial and lateral canthal tendon laxity

What age-related change is a primary cause of involutional ectropion and entropion?

Eyelid tumors (mechanical) and facial nerve paralysis (paralytic)

What mechanical force and neuromuscular condition cause ectropion?

Entropion

What medical term describes inward turning or inversion of the eyelid margin?

Canthal tendon laxity, overriding of preseptal orbicularis oculi, and disinsertion of lower lid retractors

What three anatomical factors cause involutional entropion?

Inversion of the entire eyelid margin in entropion vs. normal margin position in trichiasis

What key physical feature distinguishes entropion from trichiasis?

Trichiasis

What condition involves acquired inward misdirection of eyelashes toward the cornea due to inflammation or trauma, while the eyelid margin position remains normal?

Epilation, electrocautery of hair follicles, or surgical lid repair

What three management options treat trichiasis?

Ptosis (Blepharoptosis)

What medical term describes abnormal drooping of the upper eyelid?

Congenitally weak and fat-infiltrated levator muscle

What is the pathophysiological cause of congenital ptosis in children?

Lengthening, dehiscence, or disinsertion of the levator aponeurosis

What is the pathophysiological cause of involutional ptosis in elderly individuals?