Eyelid Anatomy Lecture 3 PDF

‭Learning Objectives‬ ‭ hat are the facial muscles that contribute to eye-opening and eyebrow movements? Be able to‬ W ‭describe the actions of each muscle‬ ‭‬ ‭Innervated by CN VII‬ ‭○‬ ‭Frontalis: raises eyebrows (surprised)‬ ‭○‬ ‭Corrugator: moves brows medially and...

‭Learning Objectives‬ ‭ hat are the facial muscles that contribute to eye-opening and eyebrow movements? Be able to‬ W ‭describe the actions of each muscle‬ ‭‬ ‭Innervated by CN VII‬ ‭○‬ ‭Frontalis: raises eyebrows (surprised)‬ ‭○‬ ‭Corrugator: moves brows medially and down (concentration)‬ ‭○‬ ‭Procerus: moves brows down and medially (aggression)‬ ‭○‬ ‭Orbicularis oculi: lowers eyebrows‬ ‭Explain the functions of the eyelids‬ ‭‬ ‭Protects the eye‬ ‭‬ ‭Pushes tear film into medial canthus (moves tears down)‬ ‭‬ ‭Spreads tear film with blinks‬ ‭‬ ‭Produces components of tear film‬ ‭Describe the muscles of the eyelid that are responsible for opening and closing the eye‬ ‭‬ ‭Identify which cranial nerves innervate each muscle‬ ‭‬ ‭Identify voluntary and involuntary actions of each muscle (smooth vs. striated)‬ ‭‬ ‭Identify and describe the actions of any additional muscles that arise from the main muscles in‬ ‭the eyelid‬ ‭‬ ‭Describe the cause of eyelid conditions that arise when each muscle is affected‬ ‭1.‬ ‭Orbicularis oculi‬ ‭a.‬ ‭LOWERS eyelid/closes eye‬ ‭b.‬ ‭CN VII‬ ‭c.‬ ‭Palpebral = light, gentle eye closure (reflex blink)‬ ‭i.‬ ‭Muscle of Riolan → (meibomian glands) maintains lids close to the globe, may‬ ‭help secrete meibum‬ ‭ii.‬ ‭Muscle of Horner → (lacrimal canaliculi) moves tears through drainage system‬ ‭d.‬ ‭Orbital = forceful eye closure (forceful blink)‬ ‭e.‬ ‭CN 7 palsy = unable to move any of the facial muscles controlled by CN (frontalis,‬ ‭corrugator, procerus, orbicularis)‬ ‭i.‬ ‭Eye unable to drain tear film (dry eye)‬ ‭2.‬ ‭Superior palpebral levator‬ ‭a.‬ ‭OPENS eyelids‬ ‭b.‬ ‭CN III superior division (upper lid only)‬ ‭c.‬ ‭Whitnall ligament → levator to move superior/inferior, supports upper lid‬ ‭d.‬ ‭Lockwood ligament → supports lower globe, houses several EOMs‬ ‭e.‬ ‭CN 3 palsy = ptosis with EOM involvement (eye turned down and out)‬ ‭3.‬ ‭Superior tarsal plate of Muller‬  a‭.‬ ‭Smooth muscle (involuntary movements)‬ ‭b.‬ ‭Additional lid elevation‬ ‭c.‬ ‭Ptosis‬ ‭4.‬ ‭Inferior tarsal plate of Muller‬ ‭a.‬ ‭Smooth muscle (involuntary movements)‬ ‭b.‬ ‭Additional lid opening‬ ‭c.‬ ‭Ptosis‬ ‭Identify and describe the location and function of the various glands in the eyelids‬ ‭‬ ‭Exocrine glands‬ ‭○‬ ‭Holocrine → secretes COMPLETE cells‬ ‭‬ ‭Meibomian glands‬ ‭‬ ‭Glands of Zeis‬ ‭○‬ ‭Apocrine → secretes PART of cytoplasm‬ ‭‬ ‭Glands of Moll‬ ‭○‬ ‭Merocrine → ACELLULAR, secretory secreition‬ ‭‬ ‭Lacrimal glands‬ ‭‬ ‭Meibomian glands‬ ‭○‬ ‭Lipid layer‬ ‭○‬ ‭Secrete meibum (lipid layer of tear film)‬ ‭○‬ ‭Within the tarsal plate‬ ‭‬ ‭Glands of Zeis‬ ‭○‬ ‭ADJACENT to hair follicle‬ ‭○‬ ‭Releases sebum into follicle support and lubrication‬ ‭‬ ‭Glands of Moll‬ ‭○‬ ‭Located NEAR hair follicle‬ ‭○‬ ‭May provide immune defense and lash lubrication‬ ‭○‬ ‭Center lined with cuboidal cells‬ ‭‬ ‭Accessory lacrimal glands‬ ‭○‬ ‭Produce aqueous layer of tear film‬ ‭○‬ ‭Gland of Krause = near fornix‬ ‭○‬ ‭Gland of Wolfring = near tarsal plate‬ ‭Describe the conjunctiva‬ ‭‬ ‭How does the tissue transition from the skin of the eyelid to the palpebral conjunctiva‬ ‭‬ ‭Palpebral vs bulbar conjunctiva tissue structure and function‬ ‭○‬ ‭Palpebral conj = lines the eyelid‬ ‭‬ ‭2 layers: non-keratinized stratified epithelium & stromal layer‬ ‭‬ ‭Goblet cells = secrete mucin layer of tear film‬ ‭‬ ‭Vit A deficiency with loss of goblet cells‬ ‭‬ ‭Stimulated by parasympathetic NS → nerves)‬ ‭‬ ‭Crypts of Henle = invaginations, lined with goblet cells‬  ‭○‬ ‭Bulbar conj = lines the white portion of the eye/lines the globe‬ ‭Describe the orbital septum and the structures that are anterior to the orbital septum‬ ‭‬ ‭Orbital septum‬ ‭○‬ ‭Protects the orbit from infection‬ ‭○‬ ‭Eyelid encompasses the structures anterior to the orbital septum‬ ‭‬ ‭Tenon capsule‬ ‭○‬ ‭Dense CT, inner to conj‬ ‭○‬ ‭Protects globe, reduces friction‬ ‭‬ ‭Canthus‬ ‭○‬ ‭Where upper and lower lids meet‬ ‭○‬ ‭Lateral (temporal)‬ ‭○‬ ‭Medial (nasal)‬ ‭‬ ‭Plica semilunaris → fold of conj,allows eye movement‬ ‭‬ ‭Caruncle → mass of modified skin‬ ‭‬ ‭Lacrimal lake → reservoir of tear collection‬ ‭‬ ‭Lid margin‬ ‭○‬ ‭Papilla → contains punctum‬ ‭○‬ ‭Punctum → opening for tear drainage‬ ‭○‬ ‭Meibomian gland poes‬ ‭○‬ ‭Cilia → eyelashes‬ ‭*epicanthal folds = vertical folds that hide medial canthus‬