A&P Ocular Adnexa

Nerve supply of eyebrows

CN VII

Frontalis

Raises eyebrows

Corrugator supercilli

Move eyebrow medially (Trouble or concentration)

Procerus

Pulls the medial side of eyebrow medially (Menace or aggression)

Function of eyebrows

Aesthetics/emotion

Protect eyeball from injury superiorly

Protect eye from bright sunlight

Helps sense stimulation and react accordinaly (A lot of nerves)

Palpebral fissure

Exposed zone between the upper and lower eyelids

Muscle opening the eye lid

Levator palpabrae superioris

CN III

Muscle closing the eye lid

Orbicularis oculi

Innervated by CN VII

Upper eye lid blood supply

internal carotid artery → the ophthalmic artery → the superior marginal arcade

Inferior eyelid carotid artery

External carotid artery → the facial artery → the angular artery → the inferior marginal artery

EAC → Angular artery

EAC → Facial artery

EAC → Inferior marginal arterial arcade

IAC → Superior marginal arterial arcard

Medial palpebral veins

Angular vein

Anterior facial vein

Inferior peripheral venous arcade

Lateral palpebral vein

Superior peripheral venous arcade

Pre-auricular lymph nodes drain the…

Lymph from upper eyelid and outer half of the lower eyelid

Submandibular lymph nodes drain the…

Lymph from a small part of middle of upper eyelid and inner half of lower eyelid

Medial eye lid margin

Lacrimal portion

Rounded, devoid of lashes or glands

Lateral eyelid margin

Ciliary portion

Rounded anterior obrder, sharp posterior boderde

Eyelid margins

2mm broad

Divided into lateral and medial portion by the punctum

Eyelashes

2-3 rows

100-150 days life span

Glands of the eyelashes

Sebaceous glands of zeiss

Modified sweat glands

Glands of moll

All open into each eyelash follicle

Distichiasis

Extra layer of eyelashes

Trichiasis

Eyelashes that curve inward

Entropion

Inward-turned eyelid

Ectropian

Outward-turned eyelid

Blepharitis

Inflammation of oil glands

Trichomegaly

Excessive lash growth

Palpebral fissure measurments

25-30 mm horizontally

10-12 mm verticall

When the eyelid closes…

Orbicularlis oculi contracts

Canalculi closes

Lacrimal sac expands (Liquid moves into lacrimal sac)

When eyelid opens…

Orbicularis oculi relaxes

Canaliculi opens

Lacrimal sac retracts (Negative pressure moves liquid down)

Septum

Thin membrane of connective tissue

Vessels and LPS muscle, enter the lids from the orbit

Tarsus

Two plates of dense connective tissue

Give shape and firmness to the lid

Meibomian gland

Lie in parralel rows in the tarsal plates

Muller muscle

Constists of the palpebral muscle of muller

Inserted on the peripheral margins of the tarsal plate

CN III innervation

Where does the muller muscle arise in the upper lid

From the fibres of the LPS muscle

Meibomian glands

Modified sebaceous glands

Located in stroma of tarsal plate

Upper contains more than lower

Ducts open at lid margin

Acini

Lined with epithelial cells

Ductule

Central duct

Excretory duct

Orifice

Normal, loss, and malformed meibomian glands

Glands of zeiss

Sebaceous glands

Attaches directly into follicles of eyelashes

Prevents eyelashes from being dry and brittle

Glands of moll

Modified apocrine sweat gland

Found on margin of the eyelid (More in lower than upper)

Functions of eyelid

1. Reconstitution of the tear film.

2. Maintain the integrity of the corneal surface.

3. Maintain the proper position of the globe within the orbital contents.

4. Regulate the amount of light allowed to enter the eye.

5. Protect from airborne particles.

6. Coverage of the eye during sleep.

Upper eyelid elevators

Primary: Levator palpebrae superiorois

Superior palpebral muscle of Muller’s

Frontalis

SPMM and frontalis important when levator is defective

Lower lid retractors

No true conterpart to the levator inferiorly

Inferior rectus is attached to the inferior tarsus. Traction exerted helps depress the lid.

Inferior palpebral muscle (Inferior version of muller’s muscle)

Orbicularis oculi

Involuntary (Automatic) blinking in early life

Rare since babies dont suffer from dryness

Rate of involuntary blinking

15 times per minute (12-20)

Blink rate increases in…

Dry conditions

Strong air currents

Surprise, anger, or fight

Blinking decreases during…

Visual observations

Movement of lids during blinking

Upper lid begins to close, no lower lid movement

Zipper-like movement from lateral canthus towards medial canthus

Voluntary blinking

Rate and degree of closure under control of the individual

Produced as a protective gesture

Simultaneous contraction of palpebral and orbital portions of the orbicularis

Winking

Unilateral voluntary lid closure

Simultaneous contraction of palpebral and orbital portions of the orbicularis

Blepharospasm

Neuro disorder affecting the muscles controlling eyelids

Starts as switching, can progress to inability opening eyes

Botox is most common treatment

Facial denervation can be done

Bell’s phenomenon

Reflex between facial and oculomotor nuclei

Eye closes → Eye rotates upward and outward

Protective mechanism

Lagophthalmos

Incomplete eyelid closer

What type of gland is lacrimal gland

Exocrine gland

Secretory lacrimal apparatus

Main lacrimal gland

Acessory secretory lacrimal glands

Glands of krause

Glands of wolfring

Excretory lacrimal apparatus

Lacrimal punctum

Lacrimal canaliculus (Sac and nasolacrimal duct)

Site of lacrimal gland

In lacrimal fossa

Formed by orbital plate of frontal bone and anterolateral roof of orbit

Acute dacryoadenitis

Inflammation of lacrimal gland

Cause: Infection, conjunctivitis, orbital cellulitis

Symptom: Inflammation of palpebral part, painful swelling laterally, S-shaped curve of lid

Excretory duct to upper fornix

Excretory ducts to lower fornix

Lacrimal ducts numbers

10-12 lacrimal ducts in superior fornix

2-5 from orbital portion

6-8 from palpebral portion

2-3 ducts inferiorly

Dacryops

Lacrimal ductal cyst

Swelling due to retention of lacrimal secretion due to blockage

Arterial supply of lacrimal gland

Internal carotid → Opthalmic artery → Lacrimal artery

External carotid artery → transverse facial artery & infraorbital artery

Venous supply of lacrimal gland

Lacrimal gland → Lacrimal vein → Superior ophthalmic vein → Internal jugular vein

Lymphatic drainage of lacrimal gland

Pre-auricular lumph nodes

Superficial parotid lymph nodes

Sensory nerve supply of lacrimal gland

Lacrimal nerve (CN V1)

Retro orbital plexus of fcial nerve (CN VII)

Sympathetic nerve supply of lacrimal gland

Carotid plexus of cervical sympathetics

Secretomotor nerve supply of lacrimal gland

Superior salivary nucleus (CN VII)

Lacrimal punctum

Upper (6mm from inner canthus) and lower punctum (6.5mm from inner canthus)

Do not overlap on eyelid closure

Sit atop papilla lacrimalis

Avascular compared to surrounding tissue

Papilla lacrimalis

Elevated mound on the lids that the punctum sit on

Lacrimal canaliculi

Passage tears go through directly after entering the puncta

Upper and lower canaliculi (For both punctum)

Lead to the lacrimal sac

Length of lacrimal canaliculi

8-12mm long

Length of course of lacrimal canaliculi

Vertical length : 2 mm

→ Angle of ampula

Horizontal length: 8-10mm

Danger triangle of the face

Bridge of nose to corners of the mouth

Union of caniculi

90% of anatomy they open into the lacrimal sac

10% of anatomy they open separately into the sac

Valve of rosenmuller

Mucosal fold that prevents tears and other debri from going sac → canaliculi

Fossa of lacrimal sac

Frontal process of maxillary bone and the lacrimal bone

Length and volume of lacrimal sac

Length: 15 mm

Volume: 20 cc

Fundus of lacrimal sac

3-5 mm

Body of lacrimal sac

10-12 mm

Interosseous part

12mm

Intrameatal part

5mm

Nasolacrimal duct

18 mm length

3mm diameter

Intraosseus part and intrameatal part

Valve of krauss

Between body of sac and naso-lacrimal duct

Hasner’s valve

Found at end of nasolacrimal sac → nasal cavity

Flow of tears

Basic secretors

Mucin secreting goblet cell of conjunctiva

Glands of krause & wolfring

Tarsal gland

Gland of zeiss & moll

Reflex secretion

Response to sensation from cornea/conj

CN V reaction

Production of more tears due to irritation of eye