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Ocular anatomy > Eyebrow and eyelid > Flashcards

Eyebrow and eyelid Flashcards

1
Q

What is the function of the eyebrow

A

Eyebrow diverst sweat/ Prevent perspiration from driping into the eyes from the forehead

Forms part of the facial expression

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2
Q

Name the four muscles that controls facial expression

A

Orbital portion of orbicularis oculi

Occipito-frontalis muscle

Corrugator supercilii

Procerus

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3
Q

Where is the orbicularis oculi located

A

Directly underneath the skin, surrounding the orbital margin

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4
Q

What is the action of the orbicularis oculi muslce

A

Closes the eyelid by voluntary control (orbital portion)

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5
Q

Where is the occipito-frontalis muscle located

A

Covers the skull, extending from the eyebrow to the back of the head

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6
Q

What is the action of the frontalis muscle

A

Draws back the scalp to raise the eyebrows, and wrinkles the forehead

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7
Q

What is the location of the corrugator supercilii

A

Beneath occipito frontalis, just above orbicularis oculi

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8
Q

What is the action of the corrugator supercilii

A

Draws the eyebrows downward and medially, producing vertical wrinkles in the forehead

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9
Q

What is location of the procerus

A

Pyramid shaped muscle at the nasl bones between the eyebrows

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10
Q

What is the action of the procerus

A

Pulls the eyebrows downward that assists in flaring the nostrils, producing horizontal frown in the forehead

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11
Q

What are the three synergistic actions of extreme upward gaze

A

Upward rotation of globe

Elevation of the upper eylids

Elevation of the eyebrows

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12
Q

Can the eyebrow be elevated voluntarily alone?

A

Yees

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13
Q

What is the nerve supply of the eyebrow

A

Motor innervator from facial nerve (CN VII)

Temporal branch
- Orbicularis oculi
- occipto-frontalis muscle
- corrugator supercilii

Upper bucal branch
- procerus

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14
Q

What is the blood supply to the eyebrow

A

Arteriral supply:
- supraorbital and supratrochlear branch of ophtlamic artery

Drainage:
- angular vein, enters the facial vein

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15
Q

Are eyebrows moved during the ordinary act of blinking

A

No

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16
Q

Where does the upper and lower eyelids meet

A

Inner canthus (medial) and outer canthus (lateral)

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17
Q

What are the structures located in the inner canthi

A

Lacus lacrimalis, where the eyelids are separeted by a small triangular space

In the center of lacus lacrimalis is th caruncle (a elevation, also known as caruncular lacrimalis)

Lateral to caruncle is the plica semilunaris (the fold of the conjuncitva)

Papilla, a small elevation 5mm from inner canthus

Punctum, located on the summit of the papilla (carries tears down the nose)

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18
Q

How long does it take for eyelashes to get replaced

A

100-150 days

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19
Q

What are the functions of the eyelashes

A

Protect the cornea

Screen and sense action

Reflex blinking
- each follicle is surrounded by a erve plexus with a very low threshold of excitation. Touching a cilium excites the nerve plexus of the folicle and produce a reflex blinking protecting the eye from the entrance of foreign particles anda against trauma

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20
Q

What are the six layers of the eyelid

A
  • Skin
  • Subcutaneous tissue
  • Striated and non striated muscle fibres
  • Orbital septum and tarsal plates
  • Submuscular areolar tissue
  • Conjunctiva
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21
Q

What is located in the skin layer of the eyelid

A

Epidermis has numerous melanocytes

Behind and between lash follicles are
- sweat glands
- Glands of Moll and Zeis (precent drying of lashes by producing lipids)

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22
Q

What is the skin continous with

A

Continous with the palpebral conjunctiva just in front of the poserior edge at the orifices of the tarsal glands

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23
Q

What is the subcutaneous tissue / areolar connective tissue layer made of and what happens if damaged

A

Loose and rich in elastic fibres

A potential cavity that allows haemorrhage (black eyes) and lymph fluids (puffy eye) to accumulate

24
Q

What are the muscles present in the striated muscles layer of the eyelid

A

Orbicularis oculi (flat and elliptical muscle, consists of thin bundles of fibres and forms the bulk of the lids)

Ciliary portion of orbicularis oculi (muscle of Riolan)

Leveator palpebral superioris (LPS)

25
What are the two portions of orbicularis oculi and what are the actions it carries out respectively
Orbital portion: voluntary closing of eyelids Palpebral portion: voluntary and involunatry closing of eyelids
26
Which nerve innervartes the orbicularis oculi muscle
Temprla and zygomatic barnches of facial nerve (CN VII)
27
What is the action of the muscle of Riolan
Ensure good closure of the lids and keeps lid margins close to the eyeball
28
What tissue is fused with the LPS and SR's muscle sheath and why
The connective tissue of the conjunctival stroma Ensures that the conjunctiva is moved as the globe or upper lid moves
29
How does the LPS attach to the medial and lateral orbital walls
Tendon of the levator expands into wide flat sheet (aponeurosis) and attach its extremitites to the medial and lateral orbital wals via expansions to the palpebral ligments Aponeurosis passes between the two parts of the lacrimal gland
30
Which nerve innervates leveator palpebrae superioris
Superior division of oculomotor nerve (CN III)
31
What is the action of the LPS
Voluntary elevation of the upper eyelid
32
What is the muscle located in the non straited muscle layer of the eyelid
Superior muller's muscles - LPS inferior lamellae contains smooth muscle whihc forms the superior tarsal of Muller
33
What is the action of the Superior Muller's muscle
Involuntary control, helps to sustain the action of LPS, keeping the lids open when awake
34
Give a breif description of the Meibomian glands
A gland that runs vertically in the tarsal plate from lid margin, orfices just in front of the posterior edge of the lid margin, marks the junction betweenm the skin and the conjunctiva
35
Where does the submuscular areolar tissue
A thin layer that lies between the orbicularis and the tarsal plate
36
What are the primary and secondary muscles in charge of eyelid opening
Primary muscle: Leveator plapebrae superioris, superior and inferior Muller muscles Secondary muscle: Occipito- frontalis muscle
37
What are the primary and secondary muscles in charge of eyelid closing
Primary muscle: Orbicularis Oculi Secondary muscle: Corrugator supercilii, procerus
38
What are the two types of blinking
Involuntary - Spontanous blinking - Reflex - Blepharospasm - Myokima Voluntary blinking - Monocular blinking - Binocular blinking
39
What is the definition of blinking
rapid closure of the eyelid
40
What is the function of blinking
Assist in the distribution of tears over the anterior surface of the eye - corneal wettability - removal of particles and fumes from sensitive cornea Helps with tear drainage at inner canthus
41
When does spontaneous blinking take place
Occus at regular periodic intervales of unknown origin during the waking hours
42
Describe in detial the process of spontaneous blinking
Lower lid remains stationary while the majority of the motion is being accomplished by the upper lid. - Completed by a narrowing of the palpebral fissures in a zipper like action from the lateral canthus toward the medial canthus
43
State the functions of spontaneous blinking
Distribute uniform layer of precorneal tear film - due to evaporation and external contaminatnts, the tear film will be disrupted in 15-20 seconds on the eye. Therefore, a periodic system of renewal is necessary to insure continous stability of the tear film Assisits in tear drainage
44
What are the different types of reflex blinking
- dazzle reflex: intiate by shining a bright light into the eye - menance reflex: intiated by the perception of sudden motion toward the eye - auditory: intiated by loud noises - tactile: intiated by touching of the cornea, conjunctiva or lashes
45
What is blepharospasm
Protective rapid lid closure Lid closure by aqueezing of the eyelids
46
What causes belpharospasm
Generally caused by ocular pain Stimulation of sensory nerve via reflex pathways connections ot the facial nerve results in contraction of orbicularis oculi
47
What is myokimia and what is it related to
Fibrillary twitching of the eyelid muscles May be related to refractive errors, fatigue, alchol, caffeine, thyrotoxicosis or mental tension
48
What is binocular blinking
both the upper and lower lids move together to close the palpebral fissure Upper lid movement is predominantly downward and somewhat nasal Lower lid movement has a primary nasal direction due to strong attachment of he muscle at the medial palpebral ligament
49
What is the function of binocular blinking
Blocks the light during sleep Protects eye from injuries Preventing precorneal tear film from evaporation
50
What is monocular blinking
A voluntary wink is a forced closure of one eye
51
Which muscles cause monocular blinking
Produced by simultaneous contraction of the palpebral and orbital protions of the orbicularis muscle
52
What is the sensory innervation of the eyelid
Upper lid: Infratrochelar, supratrochlear, supraorbital and larimal nerves Lower lid: Infratrochlear, infraorbital nerve, terminal portion fo the maxiallry division of the trigeminal nerve
53
What is the blood supply to the eyelid
Aterial supply from lateral and medial palpebral arteries, which arise from ophthalmic artery
54
What nerve is innervates eyelid opening
Oculomotor (CN III)
55
What nerve innervates eyelid closing
Facial nerve (CN VII)

Ocular anatomy (15 decks)

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