Ant Seg L2: Eyelids Anatomy

what is the thinnest skin in the body?

eyelid

what are the LAYERS of the EYELID SKIN

1. Epidermis

2. Dermis

3. Areolar Connective Tissue

4. Subcutaneous Tissue

5. Fat pad (Only in Orbital portion)

what are the LAYERS of the EPIDERMIS?

1. Keratinized superficial layer

2. Granular layer

3. Basal germinal layer

what two muscles are in the pretarsal portion of the palpebral muscle?

Horner Muscle → Deep palpebral fibers that wrap around the lacrimal canaliculi • Function: Moves tears

Riolan Muscle→ at lid margin around both sides of each meibomian gland openings • Function: Maintains lid globe congruity, express meibum

What is the Gray Line?

Anatomical landmark →Divides lid into anterior and posterior

Riolan Muscle

_____________ form a sleeve around SPL and changes it's direction to superoinferior

Ligaments

• Superior transverse ligament (Whitenall's) • Intermuscular transverse ligament

______________: (fan-like tendonous expansion of the SPL) • Pierces the orbital septum and attaches to superior tarsal plate • Attachment to skin & orbicularis = upper eyelid crease

Levator Aponeurosis

______________: Posterior inferior extension of SPL • Smooth muscles with sympathetic autonomic innervation

Tarsal Muscle of Muller

Retractor of the upper eyelids located within the orbit extending into upper eyelid

Superior Palpebral Levator Muscle

what is the function of the Capsulopalpebral fascia (lower lid aponeurosis)?

• Extension of the inferior rectus muscle sheath and inferior suspensory ligaments • Retractor of lower eyelids

What is the function of the Inferior tarsal muscle?

• Extension of inferior rectus muscle sheath inserting into lower palpebral conjunctiva and lower tarsal plate • Smooth muscle with sympathetic autonomic innervation

____________ Dense connective tissue of upper and lower eyelid that serves as a barrier and separates the anterior and posterior extent of the orbit.

Orbital Septum

the orbital septum is Continuous with _____________ of the orbital bones (orbital rim)

periorbita and periosteum

What are Zeis Glands?

Sebaceous glands • Coats lash follicles with sebum

What are Moll Glands?

• Sweat (apocrine) glands

What are Meibomian Glands?

Sebaceous glands • Embedded in tarsal plate • Secretes meibum which forms the lipid layer of tear film

What are the Accessory Lacrimal Glands?

1. Wolfring Glands • @ orbital border of tarsal plate

2. Krause Glands • @ conjunctival fornix

Secretion contribute to aqueous layer of tear film

what is the Lymphatic Drainage of the eyelid?

Lateral Conjunctiva: Preauricular Lymph Node

Medial Conjunctiva: Submandibular Lymph Node

what is the blood supply of the eyelid

Internal Carotid Artery (ICA): deep eyelid tissue

External Carotid Artery (ECA): superficial eyelid skin

what is the motor Innervation of the eyelid?

CN 7 → Zygomatic branch → Orbicularis Function: Eyelid closure

CN 3 → Superior Palpebral Levator & Inferior Rectus Function: Eyelid retraction (open)

Sympathetic nervous system→ Muller muscle, inferior tarsal muscle Function: small eyelid retraction

what is the sensory innervation of the eyelid?

CN 5

V1: Ophthalmic

V2: Maxillary Upper eyelid Lower eyelid sensation sensation

Spontaneous Blinking

15/Min Contraction of Palpebral portion of Orbicularis (-) stimulus

Reflex Blinking

Contraction of Palpebral portion of Orbicularis (+) sensory stimulus Auditory, Touch, Dazzle, Menace

Forced Blinking

Contraction of Palpebral portion + Orbital portion of Orbicularis Winking, Voluntary blink