Layers and Muscles of Eyelid – Anatomy Exam 4

Levator palpebrae superioris aponeurosis
makes studying eyelid layers complicated

Six layers of eyelid (anterior to posterior)
Skin, Subcutaneous areolar tissue (hypodermis), Striated muscle, Submuscular areolar (loose) tissue, Fibrous layer, conjunctiva

Skin layer of eyelid
one of thinnest in body; includes epidermis (4 layers), dermal papillary and reticular layers are both loose connective tissue

Subcutaneous areolar tissue (hypodermis) of eyelid
no fat (unique), made of loose connective tissue, anterior to orbicularis oculi; in upper lid, this layer is transversed by levator fibers that insert into dermis

Striated muscle of eyelid
made of orbicularis oculi muscle; arranged in budles with LPS aponeurotic fibers going between bundles

Subtarsal portion of striated muscle layer
known as muscle of Riolan; more posterior; not separate muscle, helps hold eyelid against eye

Submuscular areolar (loose) tissue layer of eyelid
pertarsal and preseptal zones of eyelid; anterior to fibrous layer

Submuscular areolar (loose) tissue layer
peripheral and marginal (only in lower) arcades

Submuscular areolar (loose) tissue layer
contains levator aponeurosis in upper lid

Submuscular areolar (loose) tissue layer
contains palpebral part of main lacrimal gland

Fibrous layer of eyelid
composed of tarsal plate and orbital septum

Tarsal plates
convex anteriorly, concave posteriorly; free/marginal border at eyelid margin, attached/orbital border

Muscle of Muller
inserts on orbital border of upper lid of tarsal plate (fibrous layer); sympathetic; not under conscious control; important in Horner’s syndrome

LPS
Levator Palpebrae Superioris

Upper muscle of Muller
originates among striated muscle fibers of LPS, then runsin conjunctival connective tissue to insert to the tarsus

Superior tarsal muscle
made up of the upper tarsal plate and muscle of Muller

Lower muscle of Muller
originates from fascial sheath of inferior rectus muscle

Orbital septum of fibrous layer
originates from orbital margin; extension of periorbita; separates anterior layers of lids from orbital fat

Lateral palpebral ligament
laterally, tarsal plates merge to form this; attaches to Whitnall’s tubercle

Medial palpebral ligament
medially, tarsal plates merge to form this; attaches to maxilla

Muscles of eyelids (3)
Levator palpebrae superioris, Muscle of Muller, Orbicularis oculi

Levator Palpebrae Superioris
raises upper eye lid, either in isolation or whenever eye is elevated; attached by aponeurosis

Aponeurosis attachment for levator palpebrae superioris
Laterally: Whitnall’s tubercle
Medially: medial palpebral ligament
Centrally: inserts into upper lid dermis, onto anterior tarsal plate

Muscle of Muller
sympathetically controlled smooth muscle, helps LPS raise upper lid; also one in lower lid that pulls it down slightly

Orbicularis Oculi
closes eyelids; no attachment tendons, just moves skin

Palpebral portion of orbicularis oculi
in eyelids; most fibers originate from medial palpebral ligament; pretarsal and preseptal portions

pretarsal
closer to margin

preseptal
further from margin

Horner’s muscle
part of palpebral orbicularis oculi; fibers originate from posterior lacrimal crest (helps drain tears into lacrimal sac)

Orbital portion of orbicularis oculi
part that surrounds orbital margin; some fibers originate from medial palpebral ligament, some from medial orbital margin

Gentle closure of eyelids
activation of palpebral orbicularis oculi

Forced closure of eyelids
activation of both orbicularis oculi portions

Muscle of Riolan
part of orbicularis oculi; in eyelid margin; extension of Horner’s muscle; keeps lid margin tightly apposed to globe (windshield wiper)

What does the lacrimal system produce and what is it’s function? Lacrimal system produces Precorneal Tear Film and it’s job is to maintain corneal function (Not active in Dry Eyes Sydrome) What are the 3 tear film layers? 1.) Lipid …

Frontalis (Frontal Belly) Description: Part of the Epicranius, above each eyebrow, starts at the top of the nose Action: Raises eyebrows, wrinkles brow Occipitalis (Occipital Belly) Description: Part of the epicranius, back of the skull. Action: Pull scalp posteriously WE …

Buccinator Used to suck in your cheeks Frontalis Used to form the horizontal frown crease on the forehead WE WILL WRITE A CUSTOM ESSAY SAMPLE ON ANY TOPIC SPECIFICALLY FOR YOU FOR ONLY $13.90/PAGE Write my sample Masseter Prime mover …

Eyebrow Tarsal Plate WE WILL WRITE A CUSTOM ESSAY SAMPLE ON ANY TOPIC SPECIFICALLY FOR YOU FOR ONLY $13.90/PAGE Write my sample Tarsal Glands Palpebral conjunctiva Cornea Palpebral fissure Eyelashes Bulbar Conjunctiva Conjunctival Sac Lacrimal Sac Medial Commissure Lacrimal Caruncle …

supraspinatus origin is supraspinatus fossa of scapula and insertion is greater tubercle of humerus. helps prevent downward dislocation of humerus coracobrachialis flexes humerus, antagonist of supraspinatus WE WILL WRITE A CUSTOM ESSAY SAMPLE ON ANY TOPIC SPECIFICALLY FOR YOU FOR …

Sarcolemma Plasma membrane of a muscle cell (muscle fiber) Myofibril Rodlike bundle of contractile filaments (myofilaments) found in muscle fibers (cells). WE WILL WRITE A CUSTOM ESSAY SAMPLE ON ANY TOPIC SPECIFICALLY FOR YOU FOR ONLY $13.90/PAGE Write my sample …

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