Ocular: Eyelids Flashcards
Eyebrows
Hair bearing skin running roughly parallel to the superior orbital rim
Functions of eyebrows :
-protection
-shield eye from dust, sweat, and light
-underlying fat layer (eyebrow protrudes)
-sensitive enough to elicit a blink
-facial expressions
Orbicularis muscle eyebrow movement:
Primary lateral depressor
Procerus muscle eyebrow function:
Medial depressor
Original and insertion of procerus muscle:
Origin: nasal bone
Insertion: frontals on each side of midline
Corrugator muscle eyebrow function:
Medial depressor
Origin and insertion of corrugator muscle:
Origin: frontal bone
Insertion: skin above medial eyebrows
Depressor supercilii muscle function:
Medial depressor (distinct from orbicularis and corrugator muscle)
Frontalis muscle eyebrow function:
Primary elevator
Origin and insertion of frontalis muscle:
Origin: high on scalp
Insertion: near superior orbital rim
CN VII temporal nerve innervates:
-upper lid orbicularis
-frontalis muscle
-corrugator muscle
CN VII zygomatic nerve innervates:
-lower lid orbicularis
CN VII angular nerve innervates:
-procerus
-corrugator
Angular nerve is formed by:
Buccal and zygomatic nerve
Epicranius muscle:
-aka frontal belly
-paired muscles running vertically
-frontalis contraction elevates eyebrows
Eyebrows elevated causes:
-horizontal forehead wrinkles
-look of surprise
Clinical correlation of epicranius muscle:
In upper lid ptosis, the frontalis muscle will be used to compensate
Corrugator supercilii muscle causes:
-vertical furrows in between brows
-sorrow, concentration, frown
-reduces sun glare
Procerus muscle causes:
-horizontal furrow across nose bridge
-menace, aggression
All muscles in the eyebrow region are sites of…
Botulinum toxin injections for blepharospasm
Shape of eyelid
Elliptical
Eyelids have complex anatomy composed of:
Skin, muscles, nerves, and blood vessels
Eyelids can be divided into 7 layers:
- Skin and subcutaneous connective tissue
- Muscles of protraction
- Orbital septum
- Orbital fat
- Muscles of retraction
- Tarsus
- Conjunctiva
In primary gaze, upper eyelid covers about ___ of the cornea
1/6th