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Layers & Components of The Eyelid Skin - thinnest in body, no subcutanous fat
- upper lid crease (fold) = levator . attachment to pretarsal orbicularis and skin; located at level of sup border of tarsus
- upper puntca is more medial
- mucocutaneous border is post to meibomian gland level
- gray line = muscle of Riolan (superficial orbicularis)
- Zeis, sebaceous glands (holocrine) with cilia
- Moll glands (only apocrine gland on lid) with skin
- 100 lashes on upper lid, 50 on lower
Blood supply - extensive anastamosis between supraorbital, lacrimal branches of ophthalmic a. (from internal carotid) and angular and temporal a. (from ext carotid)
- venous drainage: pretarsal, poatarsal
- NO lymphatics for the orbit except in conjunctiva
- eyelid medial lymphatics drain to submandibular nodes and laterally to preauricular nodes
Subcutaneous tissue - no fat, loose connective tissue holds fluid in preseptal > pretarsal area b/c less firmly attached
- main protractor
- supplied by Cranial Nerve VII, narrows PF, helps lacrimal pumporbital
- voluntary sphincter (wink, blepharospasm)
- origin at medial canthal tendon and corrugator supercilius muscle
- palpebral (pretarsal & preseptal)
- reflex blink and involuntary
- pretarsal origin at post lacrimal crest (most important to keep lid apposed to globe to let punctum lie in tear lake ) & ant limb of med canthal tendon; deep head of pretarsal m. (Horner’s tensor tarsi) encircles canaliculi to facilitate tear drainage
- upper & lower segments of pretarsal orb m. fuse to become lateral canthal tendon
- pretarsal muscle firmly adherent
- pretarsal muscle of Riolan = gray line = superficial orbicularis
- extension of periosteum
- in non-Asians, upper lid septum fuses w/levator aponeurosis. 2-5 mm above sup tarsal border; in lower lid it fuses w/capsulopalpebral fascia at or just below inf tarsal border
- passes medially in front of trochlea
- barrier to hemorrhage and infection between lid and orbit
- orb fat can herniate through septum into lids causing bags
- central orb fat pad lies behind septum, in front of levator aponeurosis.
- dense connective tissue, attach med & lat to periosteum
- 1 x 29 x 11 mm upper lids, 4 mm vertical height in lower lids
- meibomian glands are modified holocrine glands
- in upper lid marginal arcade lies 2 mm sup to lid margin, ant to tarsus
- peripheral art arcade is sup to tarsus, between levator aponeurosis, Muller’s
- mucin is produced from goblet cells
- aqueous is produced from glands of l Krause & Wolfring
- Eyelid Retractors (muscle)
- Upper lid
- Levator Palpebrae Superioris
- starts just above annulus of Zinn, then 40 mm of muscle, then 14-20 mm of aponeurosis.
- becomes vertical near Whitnall's (superotransverse) ligament (near transition m. to aponeurosis.) which is a fulcrum for vertical lid retraction (lower lid analog is Lockwood’s ligament)
- Whitnall's ligament is condensation of tissue around SR and LPS, helps suspend tissue
- levator aponeurosis: attaches to lower 1/2 of ant tarsus; lat horn of aponeurosis divides lacrimal gland into orb and palpebral lobes, attaches to lat orb tubercle; medial horn attaches to post lacrimal crest
- lid crease is formed by attachment of ant portion of aponeurosis w/ septum between the pretarsal orbicular m.’s: here the pretarsal tissues are in close apposition to underlying tarsus
- Superior Tarsal Muscle of Muller
- posterior to LPS
- sympathetically innervated; use neo drops to test function in Ptosis w/u: normal = 2 mm lift
- origin from under LPS, attaches to upper tarsus, firm attachment to conj
- Lower Eyelids
- Inferior Tarsal muscle
- Capsulopalpebral Fascia
- lower lid analog to levator aponeurosis
- originates from attachments to Inferior rectus ; therefore do vertical m. surgery before lid surgery
- inserts onto lower tarsal border
- inferior tarsal m. is analog to Muller’s, runs post to Capsulopalpebral Fascia
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