Eye Plastics Common Orbital Tumors: Overview in Children & Adults Page

Orbital Tumors

Eyelid Anatomy - 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

Orbicularis Muscle
- 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

Septum
- 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.

Tarus
- 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

Conjunctiva
- 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