Anatomy Flashcards
(326 cards)
1
Q
What is Rieger syndrome associated with?
A
Telecanthus
Rieger syndrome can present with various developmental abnormalities.
Dental = few and small teeth
Facial = maxillary hypoplasia, nasal bridge, hypertelorism (eyes set wide apart)
2
Q
What does the term ‘pental’ refer to?
A
Few & small teeth
Pental is a term used in dental anomalies.
3
Q
What is hypertelorism?
A
Eyes are set far apart
Hypertelorism is characterized by an increased distance between the eyes.
4
Q
List the layers of the eyelid.
A
1.Skin
2. Subcutaneous Areolar Layer
3. Orbicularis Layer
4. Submuscular areolar layer
5. Orbital septum
6. Posterior muscular system
7. Tarsal Plate
8. Palpebral conjunctiva
These layers serve different functions and structures within the eyelid.
5
Q
What is entropion?
A
Turning inward of the eyelid
Entropion often leads to irritation of the eye due to eyelashes rubbing against the cornea.
6
Q
What does telecanthus refer to?
A
Abnormally increased distance between medial canthi
Telecanthus is a condition that can affect the appearance of the eyes.
7
Q
What is poliosis?
A
Whitening of the eyelashes
Poliosis can be associated with various conditions, including genetic disorders.
8
Q
What is madarosis?
A
Loss of eyelashes
This condition can be caused by various factors, including trauma or disease.
Such as MGD, blepharitis, lid disease, sebaceous gland carcinoma
9
Q
What is trichiasis?
A
Turning inward of eyelashes
Trichiasis is often secondary to conditions like entropion.
10
Q
What is phthiriasis palpebrarum?
A
Infection of the eyelashes caused by Phthirus pubis
- pubic crab lice
11
Q
Describe the skin layer of the eyelid.
A
Thin layer containing fine hairs, sweat glands, and sebaceous glands
This layer is unique as it is the thinnest skin in the body and contains no fat.
12
Q
What does the subcutaneous areolar layer contain?
A
Loose connective tissue and levator aponeurosis
The levator aponeurosis is crucial for eyelid elevation.
13
Q
What is the orbicularis layer?
A
Contains the palpebral portion of the orbicularis oculi
The orbicularis oculi is a muscle responsible for closing the eyelids.
14
Q
What is a characteristic of the eyelid skin?
A
Contains no fat
This anatomical feature contributes to the eyelid’s flexibility and function.
15
Q
What is the role of the eyelid?
A
Keeps the eyeball divided into anterior & posterior portions
The eyelid protects the eye and maintains moisture.
16
Q
Which cranial nerve is responsible for eyelid expression? (Facial expression)
A
CN VII (facial nerve)
CN VII innervates the muscles responsible for facial expressions, including the eyelids.
17
Q
What happens during paralysis of CN VII?
A
Causes a brow to be lowered on the affected side and can lead to lagophthalmos
Lagophthalmos refers to the inability to close the eyelids fully.
18
Q
What are the two portions of the orbicularis oculi?
A
- Orbital portion
- Palpebral portion
These portions serve different functions in eyelid movement.
19
Q
What is the function of the orbital portion of the orbicularis oculi?
A
Used for forced closure of the eyelids
The orbital portion attaches to the orbital margins and extends outward.
20
Q
What is the function of the palpebral portion of the orbicularis oculi?
A
Used for spontaneous and reflex blinking
This portion helps in gentle eyelid closure.
21
Q
What is the muscle of Riolan?
A
Most superficial portion of the orbicularis oculi that keeps the lid margin tightly applied to the globe
Also known as the pars ciliaris.
22
Q
What is the gray line?
A
A groove located between the eyelash insertions and the meibomian glands
It serves as a surgical landmark during lid repair.
23
Q
What condition results from paralysis of the orbicularis oculi?
A
Ectropion
Ectropion is characterized by the lower eyelid drooping away from the globe.
24
Q
What is the muscle of Horner?
A
Consists of fibers from the orbicularis that help drain tears into the lacrimal sac
Also referred to as the pars lacrimalis.
25
What is the anatomical origin of the muscle of Horner?
Originates from the posterior lacrimal crest and fascia of the lacrimal sac
## Footnote
It encircles the canaliculi to assist in tear drainage.
26
What does paralysis of the orbicularis oculi lead to?
Drooping of the lower eyelid and potential eversion of the lid
## Footnote
This can also lead to discomfort and red eye due to improper eyelid function.
27
Fill in the blank: The gray line divides the lid into _______ and posterior portions.
anterior
## Footnote
This anatomical feature is important for surgical procedures.
28
What is the submuscular areolar layer?
Thin layer of loose connective tissue between the orbicularis and the orbital septum
## Footnote
Contains the levator aponeurosis and the palpebral portion of the main lacrimal gland
29
What is the function of the orbital septum?
Serves as a barrier to the orbit in the upper and lower eyelids
## Footnote
Prevents fat from falling onto the lid margins and keeps infections localized to the anterior portion of the eyelid
30
True or False: The orbital septum protects the lacrimal sac from infection.
False
## Footnote
The lacrimal sac is anterior to the attachment of the orbital septum
31
What does preseptal cellulitis refer to?
An infection that occurs anterior to the orbital septum
## Footnote
Commonly seen in cases of eyelid infections
32
What is orbital cellulitis?
An infection that occurs posterior to the orbital septum
## Footnote
More serious than preseptal cellulitis, often involving the orbit itself
33
What are the components of the posterior muscular system of the eyelid?
Superior levator palpebrae muscle, superior tarsal muscle, inferior tarsal muscle
## Footnote
These muscles control eyelid elevation and positioning
34
Where does the superior palpebral levator muscle originate?
From the lesser wing of the sphenoid at the orbital apex
## Footnote
It serves as the main retractor of the upper eyelid
35
What is the role of Whitnall's ligament?
Serves as a fulcrum for the levator muscle
## Footnote
Changes the course of the muscle, allowing it to perform its function effectively
36
Fill in the blank: The levator muscle extends into the eyelid as a fan-shaped tendon known as the _______.
levator aponeurosis
## Footnote
This tendon sends fibers anteriorly through the orbital septum
37
What is the significance of the medial and lateral horns of the levator aponeurosis?
The lateral horn attaches to Whitnall's ligament; the medial horn merges with the medial palpebral ligament
## Footnote
Important for the structural integrity and function of the eyelid
38
What is the clinical implication of CN III palsy on the eyelid?
Results in ptosis, or drooping of the upper eyelid
## Footnote
CN III is responsible for innervating the levator palpebrae muscle
39
What is the function of the levator palpebrae superioris?
Elevates the upper eyelid
40
What forms the superior palpebral furrow?
Insertion of the levator aponeurosis into the skin of the upper eyelid
41
What forms the inferior palpebral furrow?
Indirect attachment of the inferior rectus muscle into the skin of the lower eyelid
42
What separates the tarsal and orbital portions of the eyelid?
Eyelid furrows
43
What is the role of the Muscle of Muller?
Provides minor retraction of the upper eyelid and widens the palpebral fissure
44
Which receptors does the Muscle of Muller respond to?
Alpha-1 adrenergic receptors
45
What is another name for the Muscle of Muller?
Superior tarsal muscle
46
Where does the inferior tarsal muscle originate?
Fascial sheath of the inferior rectus
47
What causes mild upper lid ptosis in Horner's syndrome?
Lack of sympathetic innervation to the Muscle of Muller
48
What is the result of CN III palsy?
Significant upper lid ptosis
49
What condition can cause a 'stare appearance' in patients?
Thyroid eye disease
50
What is the normal interpalpebral fissure distance in adults?
10-12 mm
51
Which cranial nerve opens the eye?
Cranial Nerve III (CN III)
52
Which cranial nerve closes the eye?
Cranial Nerve VII (CN VII)
53
______ is the smooth muscle innervated by the sympathetic nervous system that raises the eyelid.
Muscle of Muller
54
True or False: Cocaine can maintain the eye being open.
True
55
What is the effect of sympathetic input on pupil dilation?
Will not dilate the pupil in the absence of sympathetic input
56
List the adrenergic receptors available to bind norepinephrine.
* A1
* A2
* B1
* B2
57
What is the primary function of the Meibomian glands?
To produce the anterior lipid layer of the tear film
## Footnote
Meibomian glands are large sebaceous glands located within the tarsal plate
58
How many Meibomian glands are approximately in the upper eyelid?
About 25 Meibomian glands
## Footnote
There are approximately 20 glands in the lower eyelid
59
What type of tissue composes the tarsal plate?
Dense irregular connective tissue
## Footnote
This tissue provides rigidity to the eyelids
60
What are the two layers of the palpebral conjunctiva?
1. Epithelial layer
2. Stroma
## Footnote
The epithelial layer contains goblet cells that produce mucin for the tear film
61
Where are goblet cells predominantly found?
In the inferonasal fornix and on the bulbar conjunctiva
## Footnote
Most concentrated temporally
62
What does the stroma of the palpebral conjunctiva contain?
Superficial lymphoid layer and deep fibrous layer
## Footnote
The superficial lymphoid layer is immunologically active
63
What is the function of the Glands of Zeis?
To lubricate the eyelashes
## Footnote
They are modified sebaceous glands associated with eyelash follicles
64
True or False: The Glands of Moll are modified sebaceous glands.
False
## Footnote
Glands of Moll are modified apocrine glands located near the lid margin
65
Fill in the blank: The upper and lower tarsal plates combine to form the _______.
Medial and lateral palpebral ligaments
## Footnote
The medial palpebral ligament attaches to the maxillary bone
66
What type of immune cells are found in the superficial lymphoid layer of the conjunctiva?
IgA, macrophages, mast cells, PMNs, eosinophils
## Footnote
This layer is very immunologically active
67
What are the accessory lacrimal glands located in the fornices of the conjunctiva called?
Glands of Krause
## Footnote
They are considered merocrine glands
68
What is exocytosis?
A process where cells secrete substances by expelling them from vesicles, allowing the cells to remain intact.
69
What are the Glands of Wolfring?
Accessory lacrimal glands that are larger and less numerous than the glands of Krause, located predominantly in the tarsal conjunctiva.
70
What type of glands are the Meibomian glands and glands of Zeis?
Holocrine glands.
71
What type of glands are the Glands of Moll and goblet cells?
Apocrine glands.
72
What type of glands are the accessory lacrimal glands?
Merocrine glands.
73
During holocrine secretion, what happens to the cell?
The whole cell is shed into the lumen.
74
During apocrine secretion, what occurs?
A portion of the plasma membrane buds off the cell and enters the lumen for secretion.
75
In merocrine secretion, how do cells secrete their substances?
Cells secrete their substances by exocytosis and remain completely intact after secretion.
76
True or false
There are more glands of Krause than Wolfring
True
* more glands of Krause but wolfing glands are larger
77
What is the orbicularis oculi?
A muscle of the eyelids with concentric fibers that act as a sphincter to close the eyelids
## Footnote
It consists of palpebral and ciliary portions.
78
Which nerve innervates the orbicularis oculi?
Zygomatic branch of the facial nerve
## Footnote
It provides voluntary motor innervation.
79
What type of innervation does the muscle of Muller receive?
Involuntary motor innervation from the sympathetic nervous system
## Footnote
This muscle assists in elevating the upper eyelid.
80
What branches supply sensory innervation to the upper eyelid?
Frontal (supraorbital and supratrochlear) and lacrimal branches of V1 (ophthalmic nerve)
## Footnote
These branches are responsible for sensory perception in the upper eyelid.
81
Which branches innervate the lower eyelid?
Infraorbital and zygomaticofacial branches of V2 (maxillary nerve)
## Footnote
These branches provide sensory innervation to the lower eyelid.
82
What is the role of the infratrochlear nerve?
Innervates the medial aspect of the upper and lower eyelids
## Footnote
It branches from the nasociliary nerve of V1.
83
What arteries supply the deeper eyelid tissue?
Lateral and medial palpebral arteries, branches of the ophthalmic artery
## Footnote
These arteries are crucial for blood supply to the eyelids.
84
Where are the palpebral arcades located?
In the submucosal areolar layer of the upper and lower eyelids
## Footnote
They are formed by the union of the medial and lateral palpebral arteries.
85
What are the two main types of palpebral arcades?
Marginal palpebral arcades and Peripheral palpebral arcades
## Footnote
Marginal palpebral arcades are located closest to the eyelid margin, while Peripheral palpebral arcades supply the fornices and the posterior conjunctiva.
86
What is the role of the anterior ciliary arteries?
Provide circulation to the bulbar conjunctiva and the ciliary body
## Footnote
This explains why patients with uveitis can experience circumlimbal injection and decreased aqueous humor production in the involved eye.
87
Which arteries supply the superficial areas of the eyelid?
Facial artery
## Footnote
The facial artery branches off the external carotid artery.
88
What condition can lead to circumlimbal injection?
Uveitis
## Footnote
Uveitis can cause inflammation leading to circumlimbal injection and decreased aqueous humor production.
89
Fill in the blank: The _______ supplies circulation to the deeper eyelid structures.
Arcades
90
True or False: The veins of the eyelids drain into the palpebral and ophthalmic arteries.
False
## Footnote
The veins of the eyelids drain into the palpebral and ophthalmic veins, not arteries.
91
What is the function of the medial palpebral artery?
Supplies circulation to the medial aspect of the eyelid
## Footnote
It is a branch of the ophthalmic artery.
92
What is the approximate volume of aqueous humor in the anterior chamber?
200 microliters
93
List the main branches of the external carotid artery that supply the eyelids.
* Facial artery
* Lacrimal artery
94
What do the superior and inferior marginal arcades supply?
The eyelid margins
## Footnote
They are important for vascular supply to the eyelid.
95
Circumlimbal injection
Enlargement of episcleral vessels in the region of the CB
96
What does EKC stand for?
Epidemic Keratoconjunctivitis
97
What are the symptoms of Epidemic Keratoconjunctivitis?
- burning
- Itching
- FBS
- Tearing
- Photophobia
98
What is the self-resolving time frame for EKC?
2-3 weeks
99
What type of lymphatic drainage occurs in the conjunctiva?
Lateral lymphatics drain into the parotid (preauricular) lymph nodes; Medial lymphatics drain into the submandibular lymph nodes
100
True or False: Simple bacterial conjunctivitis presents with preauricular lymphadenopathy.
False
101
True or false
Epidemic keratoconjunctivitis has positive preauricular lymphadenopathy?
True
102
What is the primary function of the eyebrows?
protection and facial expression
103
What reflex do the cilia of the eyebrows and eyelashes elicit?
blink reflex
104
What muscle is the main elevator of the eyebrows?
Frontalis
105
Fill in the blank: The frontalis muscle helps to compensate for _______.
ptosis
106
What does the corrugator muscle do?
Medial depressor of the eyebrow
107
What is the function of the procerus muscle?
Pulls the skin between the eyebrows downward for an appearance of menace or aggression
108
Where does the procerus muscle originate?
on the nasal bone (bridge of the nose)
109
What is the primary lateral depressor of the eyebrow?
Orbicularis Oculi
110
What is a key characteristic of the frontalis muscle?
Fibers run vertically to raise the eyebrow for a look of surprise or attention
111
What type of wrinkles does the corrugator muscle produce?
vertical wrinkles of the forehead
112
What appearance does the corrugator muscle create?
a look of concentration
113
What is the role of the Orbicularis Oculi muscle?
to depress the eyebrow laterally
114
What is Parinaud's oculoglandular syndrome characterized by?
significant preauricular and submandibular lymphadenopathy
115
Where is the lacrimal gland located?
In a fossa on the temporal side of the frontal bone
116
What are the two portions of the lacrimal gland?
Orbital and palpebral portions
117
What type of gland is the lacrimal gland?
Tubuloalveolar exocrine gland
118
How does the lacrimal gland release its products?
Via merocrine secretion
119
What supplies blood to the lacrimal gland?
Glandular branches of the lacrimal artery
120
How is the lacrimal gland drained?
By the lacrimal vein
121
What is unique about the lymphatic vessels of the lacrimal gland?
They are the ONLY lymphatic vessels of the orbit
122
Where do the lymphatic vessels of the lacrimal gland drain?
Into the parotid lymph nodes
123
What type of innervation does the lacrimal gland receive?
Parasympathetic innervation from the lacrimal nerve of the pterygopalatine ganglion of CN VII
124
What does parasympathetic stimulation of the lacrimal gland cause?
Secretion of the aqueous layer of the tears
125
Do sympathetic nerve fibers innervate the lacrimal gland?
Yes, some sympathetic nerve fibers follow the lacrimal artery
126
What is acute dacryoadenitis?
An infection and/or inflammation of the lacrimal gland
127
What can acute dacryoadenitis result in?
Acute swelling and discomfort in the upper lateral eyelid
128
What causes acute dacryoadenitis?
Staphylococcus infection
129
What are chronic causes of dacryoadenitis?
Sarcoidosis
*Auto-immune
*causes non-granulomatous uveitis
*
130
What are accessory lacrimal glands?
Glands that have the same histological makeup as the main lacrimal gland
131
Name two types of accessory lacrimal glands.
Glands of Wolfring and glands of Krause
132
Where are accessory lacrimal glands located?
In the subconjunctival tissue from the fornix up to the tarsal plate
133
Make sure you know the anatomy of nasolacrimal drainage system!
134
What are the 2 divisions of lacrimal gland?
Palpebral and orbital
* divided by tendon of levator (SLP)
135
What are lacrimal puncta?
Small openings located within a ring of connective tissue called the lacrimal papilla
136
What is the function of the lacrimal papilla?
Responsible for keeping the puncta open
137
What is the length of the canaliculi?
10 mm long
138
What type of epithelium lines the canaliculi?
Stratified and pseudostratified epithelium
139
Describe the path of the canaliculi.
Initially runs vertically 2 mm, then travels medially 8 mm before joining the common canaliculus
140
What prevents back flow into the canaliculi?
The angle at which the common canaliculus enters the lacrimal sac
141
What muscle surrounds the canaliculi?
Muscle of Horner
142
What is the role of the muscle of Horner during eyelid closure?
Contracts the canaliculi to assist in tear drainage
143
Where is the lacrimal sac located?
Within a fossa in the medial orbital wall formed by the lacrimal and maxillary bones
144
What is the length of the lacrimal sac?
10-12 mm long
145
What type of epithelium lines the lacrimal sac?
Double epithelium with superficial columnar and deep basal layers
146
What additional structures are found in the lacrimal sac?
Microvilli and goblet cells
147
What is the lacrimal sac continuous with?
The nasolacrimal duct
148
What is located posterior to the lacrimal sac?
The orbital septum and the check ligament of the medial rectus
149
True or False: The lacrimal sac is less susceptible to infection due to its position.
False
150
What does NLDO stand for?
Nasolacrimal duct obstruction
151
What is a common cause of unilateral tearing in adults?
Involutional stenosis (age)
152
What is Jones I testing used for?
To assess nasolacrimal duct function
153
What condition can untreated nasolacrimal duct obstruction lead to?
Dacryocystitis
154
What is dacryocystitis?
An infection of the lacrimal sac
* usually occurs as a result of nasolacrimal duct obstruction
155
What anatomical features form the nasolacrimal duct?
Posterior lacrimal crest of the maxillary bone and the inferior concha
156
How long is the nasolacrimal duct?
15 mm
157
What lines the nasolacrimal duct?
Double epithelium, microvilli, and goblet cells
158
Where does the nasolacrimal duct terminate?
Inferior meatus of the nasal cavity
159
What is the function of the Valve of Hasner?
Prevents back flow of nasal fluids into the lacrimal drainage system
160
What structures are contained within the orbit?
Globe of the eye
extraocular muscles
optic nerve
connective tissue
adipose tissue
161
What is thyroid eye disease?
An autoimmune response against the connective tissue and adipose tissue within the orbit
162
What symptoms are associated with thyroid eye disease?
Swelling, inflammation, proptosis, lid retraction, EOM restrictions, optic nerve compression
163
What are the two compartments of adipose tissue in the orbit?
* Intraconal adipose tissue
* Extraconal adipose tissue
164
Where is intraconal adipose tissue located?
Within the muscle cone of the four recti muscles
165
Where is extraconal adipose tissue found?
Outside the muscle cone between the EOMs and the walls of the orbit
166
What are extraocular muscles?
Extrinsic muscles of the eye that attach to the sclera
167
Fill in the blank: The nasolacrimal duct is lined with a _______.
Double epithelium
168
True or False: The nasolacrimal duct is involved in the drainage of tears.
True
169
What is denser in extraocular muscles (EOMs)?
Blood supply and nerve supply
## Footnote
EOMs have a denser blood supply and a more finely tuned nerve supply.
170
What combination of muscle fibers allows EOM movements to be faster and more fatigue resistant?
White (fast) and red (slow but sustaining) muscle fibers
## Footnote
This unique combination contributes to the performance of EOMs.
171
Where does the superior rectus muscle originate?
Common tendinous ring anterior to the superior orbital fissure
## Footnote
It inserts 7.7 mm from the limbus.
172
What connects the sheath covering the superior rectus?
Sheath of the superior levator palpebrae and connective tissue of the superior conjunctival fornix
## Footnote
These connections raise the lid when the eye is in up gaze.
173
Where does the inferior rectus muscle originate?
Common tendinous ring at the infraoptic tubercule
## Footnote
It inserts 6.5 mm from the limbus.
174
What structure does the sheath of the inferior rectus combine with?
Sheath of the inferior oblique muscle
## Footnote
This forms the suspensory ligament of Lockwood.
175
What does the suspensory ligament of Lockwood attach to?
Inferior tarsal plate, zygomatic bone, and lacrimal bone
## Footnote
It provides support for the globe.
176
Where does the lateral rectus muscle originate?
Common tendinous ring at the spina recti lateralis
## Footnote
It inserts 6.9 mm from the limbus.
177
What anchors the lateral rectus muscle?
Lateral check ligament to Whitnall's tubercule
## Footnote
This is located on the zygomatic bone of the orbit.
178
Where does the medial rectus muscle originate?
Common tendinous ring
## Footnote
It inserts 5.5 mm from the limbus.
179
What anchors the medial rectus muscle?
Medial check ligament to medial orbital septum and other structures
## Footnote
This includes the bone behind the posterior lacrimal crest, the caruncle, and the plica semilunaris.
180
Superior rectus
Innervated by CN?
Origin?
Insertion?
Primary, secondary and tertiary actions?
CN III
origin: common tendinous ring
Inserts: 7.7 mm from limbus
1. Elevation
2. Intorsion
3. ADDuction
181
Inferior rectus
Innervated by CN?
Origin?
Insertion?
Primary, secondary and tertiary actions?
CN III
origin: common tendinous ring
Insertion: 6.5mm from limbus
1. Depression
2. Extorsion
3. ADDuction
182
What is the insertion distance of the Superior Rectus muscle from the limbus?
7.7 mm
## Footnote
The Superior Rectus (SR) inserts furthest from the limbus compared to other recti muscles.
183
What is the insertion distance of the Lateral Rectus muscle from the limbus?
6.9 mm
## Footnote
The Lateral Rectus (LR) inserts at 6.9 mm from the limbus.
184
What is the insertion distance of the Inferior Rectus muscle from the limbus?
6.5 mm
## Footnote
The Inferior Rectus (IR) inserts at 6.5 mm from the limbus.
185
What is the insertion distance of the Medial Rectus muscle from the limbus?
5.5 mm
## Footnote
The Medial Rectus (MR) inserts closest to the limbus at 5.5 mm.
186
Where do all recti muscles originate from?
Common Tendinous Ring (CTR)
## Footnote
All recti muscles originate from the CTR.
187
What anatomical structure is considered the physiological origin of the Superior Oblique muscle?
Trochlea
## Footnote
The trochlea changes the direction of action for the Superior Oblique.
188
Where does the Inferior Oblique muscle originate?
Maxillary bone
## Footnote
The Inferior Oblique originates anteriorly at the maxillary bone, posterior to the medial orbital rim.
189
What is the primary action of the Lateral Rectus muscle?
Abduction
## Footnote
The primary action for the Lateral Rectus is abduction of the eye.
190
What is the primary action of the Medial Rectus muscle?
Adduction
## Footnote
The primary action for the Medial Rectus is adduction of the eye.
191
What is the primary action of the Superior Rectus muscle?
Elevation
## Footnote
The primary action for the Superior Rectus is elevation of the eye.
192
What is the primary action of the Inferior Rectus muscle?
Depression
## Footnote
The primary action for the Inferior Rectus is depression of the eye.
193
What is the primary action of the Superior Oblique muscle?
Intorsion
## Footnote
The primary action for the Superior Oblique is intorsion of the eye.
194
What is the primary action of the Inferior Oblique muscle?
Extorsion
## Footnote
The primary action for the Inferior Oblique is extorsion of the eye.
195
True or False: The primary action for the obliques is extorsion.
False
## Footnote
The primary action for the obliques is intorsion.
196
Fill in the blank: The superior and inferior obliques are responsible for pure _______ and _______ respectively when the eye is adducted.
depression, elevation
## Footnote
This occurs when the eye is adducted 51-5 degrees towards the midline.
197
Fill in the blank: The superior and inferior recti muscles are responsible for pure _______ and _______ respectively when the eye is abducted.
elevation, depression
## Footnote
This occurs when the eye is abducted 23 degrees away from the midline.
198
What are the primary and secondary actions of the Superior Oblique muscle?
Primary: Intorsion, Secondary: Adduction
## Footnote
The Superior Oblique muscle primarily intorts the eye and can secondarily adduct.
199
What are the primary and secondary actions of the Inferior Oblique muscle?
Primary: Extorsion, Secondary: Abduction
## Footnote
The Inferior Oblique muscle primarily extorts the eye and can secondarily abduct.
200
What are the two muscular branches from the ophthalmic artery that supply the EOMs?
1. Superior lateral branch
2. Inferior medial branch
## Footnote
These branches are responsible for supplying different extraocular muscles.
201
Which extraocular muscles are supplied by the superior lateral branch of the ophthalmic artery?
SR, LR, SO
## Footnote
SR = Superior Rectus, LR = Lateral Rectus, SO = Superior Oblique.
202
Which extraocular muscles are supplied by the inferior medial branch of the ophthalmic artery?
MR, IR, IO
## Footnote
MR = Medial Rectus, IR = Inferior Rectus, IO = Inferior Oblique.
203
What minor arteries may provide blood supply to the EOMs?
Lacrimal artery, supraorbital artery, infraorbital artery
## Footnote
These arteries contribute to the blood supply but are not the main sources.
204
Which cranial nerve innervates the superior rectus muscle?
CN III (superior division)
## Footnote
CN III is the oculomotor nerve.
205
Which muscles are innervated by the inferior division of CN III?
IR, IO, MR
## Footnote
IR = Inferior Rectus, IO = Inferior Oblique, MR = Medial Rectus.
206
Which cranial nerve innervates the lateral rectus muscle?
CN VI
## Footnote
CN VI is the abducens nerve.
207
Which cranial nerve innervates the superior oblique muscle?
CN IV
## Footnote
CN IV is the trochlear nerve.
208
What is the orbital fascia also known as?
Periorbita or orbital periosteum
## Footnote
This fascia plays a crucial role in the structure of the orbit.
209
What is the primary composition of the orbital fascia?
Dense connective tissue
## Footnote
This composition provides support and structure within the orbit.
210
What does the orbital fascia provide support to?
Blood vessels within the orbit
## Footnote
It also serves as a point of attachment for muscles, tendons, and ligaments.
211
How is the orbital fascia related to the dura mater?
Continuous with the dura mater surrounding the brain and optic nerve
## Footnote
This connection occurs within the optic canal.
212
What is the role of the anterior orbital fascia?
Forms the orbital septum and prevents prolapse of orbital fat
## Footnote
It also acts as a barrier against orbital infections.
213
Fill in the blank: The orbital fascia contributes to the formation of the _______.
CTR (common tendinous ring)
## Footnote
This structure is significant for muscle attachments.
214
What does the orbital fascia cover besides the bones of the orbit?
Lacrimal gland, lacrimal sac, nasolacrimal canal
## Footnote
This coverage is essential for the function of the lacrimal system.
215
What forms the base of the cranium?
The body of the sphenoid bone
## Footnote
The sphenoid bone has a middle portion known as the body, which is crucial for cranial structure.
216
Where is the optic canal located in relation to the sphenoid bone?
Just lateral to the center of the sphenoid body
## Footnote
The optic canal is essential for the passage of the optic nerve and ophthalmic artery.
217
What is the sella turcica?
A depression in the body of the sphenoid bone that houses the pituitary gland
## Footnote
The sella turcica is a key anatomical feature relevant for endocrine function.
218
What lies superior to the pituitary gland?
The optic chiasm
## Footnote
This relationship is important for understanding visual field deficits caused by pituitary tumors.
219
What visual field defect can result from damage to nasal retinal fibers due to a pituitary tumor?
Bitemporal hemianopsia
## Footnote
This condition occurs when the fibers that cross at the optic chiasm are affected.
220
What are the two wings of the sphenoid bone?
Lesser wing and Greater wing
## Footnote
Each wing has specific anatomical connections and features.
221
What does the lesser wing of the sphenoid connect with?
The frontal bone
## Footnote
This connection helps form the roof of the orbit.
222
What structures are contained within the optic canal?
Optic nerve and ophthalmic artery
## Footnote
These structures are vital for vision and blood supply to the eye.
223
What does the greater wing of the sphenoid connect with?
The zygomatic bone
## Footnote
This connection helps form the lateral wall of the orbit.
224
What are the three important foramina located in the greater wing of the sphenoid?
Foramen rotundum, Foramen ovale, Foramen spinosum
## Footnote
Each foramen has a specific function related to nerve and artery passage.
225
What does the foramen rotundum transmit?
Maxillary division (V2) of the trigeminal nerve
## Footnote
This foramen is crucial for sensory innervation to the mid-facial region.
226
What does the foramen ovale transmit?
Mandibular division (V3) of the trigeminal nerve and the lesser superficial petrosal nerve
## Footnote
This foramen is essential for motor innervation to the muscles of mastication.
227
What does the foramen spinosum transmit?
Middle meningeal artery
## Footnote
This artery supplies the meninges and is important for cranial blood supply.
228
What is the Superior Orbital Fissure (SOF)?
An opening between the greater and lesser wings of the sphenoid bone
## Footnote
The SOF allows passage for several cranial nerves and vascular structures.
229
What lies just posterior to the Superior Orbital Fissure?
Cavernous sinus
## Footnote
This structure is significant for venous drainage and cranial nerve relationships.
230
What is the Common Tendinous Ring (CTR)?
A circular band of connective tissue that lies just anterior to the SOF
## Footnote
The CTR serves as the origin for the recti muscles of the eye.
231
What is another name for the Common Tendinous Ring?
Annulus of Zinn
## Footnote
This alternative name is often used in anatomical contexts.
232
Which cranial nerves pass through both the SOF and the CTR?
CN III, CN VI, Nasociliary nerve
## Footnote
These nerves are crucial for ocular function and control.
233
True or False: The sympathetic root of the ciliary ganglion travels with the nasociliary nerve.
True
## Footnote
This relationship is important for understanding autonomic innervation to the eye.
234
Which corneal layer increases in size (3x) throughout a person’s lifetime?
Descemet’s membrane
* basement membrane for corneal endothelium and is continuously secreted by the corneal endothelial cells
* approximately 3 microns thick in kids and increases to 10 microns by adulthood
235
Forebrain includes? (7)
1. Cerebrum
2. Olfactory lobes
3. Thalamus
4. Hypothalamus
5. Limbic system
6. Pituitary gland
7. Pineal gland
236
Midbrain includes? (3)
Tectum
Substantia nigra
Red nucleus
237
Hindbrain includes?
Cerebellum
Pons
Medulla oblongata
238
“The anvil” is the name of what bone in the middle ear?
The incus
239
How does sound travel through the ear?
1. Sound is funneled by the pinna (outer ear)
2. Into the auditory canal
3. Then to the tympanic membrane
4. Vibration of membrane transfers sound energy to the malleus (the hammer)
5. Which passes it to the incus (anvil)
6. Then to the stapes (stirrup)
240
What is the foramen magnum?
The opening at the base of the occipital lobe for the spinal cord
## Footnote
Foramen magnum literally means 'great hole'.
241
What is the function of the foramen ovale?
Serves as a passageway for several nerves including the mandibular nerve
## Footnote
The foramen ovale courses through the posterior portion of the sphenoid bone.
242
What nerve passes through the foramen rotundum?
Maxillary division of the trigeminal nerve
## Footnote
The foramen rotundum allows this nerve to pass through the sphenoid bone and the pterygopalatine fossa.
243
What does the foramen spinosum transmit?
Middle meningeal artery
## Footnote
The foramen spinosum is located on the greater wing of the sphenoid bone.
244
Which foramina are located in close proximity to each other?
Foramen ovale, foramen rotundum, and foramen spinosum
## Footnote
These foramina are all situated near each other in the sphenoid bone.
245
What is the origin of the superior oblique?
Lesser wing of sphenoid near the frontoethmoid structure
246
The tendon of which EOM courses through the trochlea?
Superior oblique
* innervated by trochlear nerve (CN IV)
247
Which cell produces ground substance found in connective tissue?
Fibroblasts
* ground substance and fibers make up connective tissue matrix
248
Which cells produce and release heparin and histamine?
Mast cells
249
What are Schwann cells?
Non-neuronal cells of the peripheral nervous system that coat axons in a myelin sheath
## Footnote
This myelin sheath greatly increases the speed of conduction of action potentials.
250
How do oligodendrocytes function in the central nervous system?
They insulate neuronal cell axons
## Footnote
Oligodendrocytes have a similar function to Schwann cells but are specific to the central nervous system.
251
What role do astrocytes play in the brain?
They offer support and structure to the brain
## Footnote
Astrocytes are the most numerous type of glial cell.
252
What is the function of the blood-brain barrier?
To inhibit toxic substances of the blood from entering the brain
## Footnote
Astrocytes play a large role in the formation of this barrier.
253
What do astrocytes do with neurotransmitters?
They remove neurotransmitters from synaptic zones
## Footnote
This process helps maintain neurotransmitter balance in the brain.
254
What is the role of microglial cells?
They act as macrophages in response to injury, disease, or infection
## Footnote
Microglial cells are capable of phagocytosis.
255
Where are ependymal cells found?
Lining cavities of the central nervous system and walls of the ventricles of the brain
## Footnote
Ependymal cells form the epithelium of the choroid plexus.
256
What does the choroid plexus secrete?
Cerebrospinal fluid
## Footnote
Ependymal cells collectively form the epithelium of the choroid plexus.
257
True or False: Schwann cells are found in the central nervous system.
False
## Footnote
Schwann cells are specific to the peripheral nervous system.
258
Fill in the blank: The most numerous type of glial cell is _______.
astrocytes
## Footnote
Astrocytes support the structure of the brain.
259
What is the primary function of microglial cells?
Phagocytosis
## Footnote
They are called into action during injury, disease, or infection.
260
What is the cavernous sinus?
A large venous channel on each side of the body of the sphenoid extending from the medial end of the superior orbital fissure to the petrous portion of the temporal bone and lateral to the sella turcica.
261
Which important structures are located in the medial portion of the cavernous sinus?
Internal carotid artery and abducens nerve (CN VI).
262
Which cranial nerves are found within the lateral portion of the cavernous sinus?
Oculomotor (CN III), trochlear (CN IV), ophthalmic, and maxillary branches of the trigeminal (CN V).
263
What unique feature does the cavernous sinus have regarding arterial and venous structures?
It is the only location where an artery travels through a venous structure.
264
What can a rupture of the internal carotid artery within the cavernous sinus create?
An arteriovenous fistula.
265
What is cavernous sinus syndrome usually a result of?
Pituitary masses or other masses compressing the region.
266
What symptoms can arise from cavernous sinus syndrome?
Ophthalmoplegia, maxillary sensory loss, and a fixed, dilated pupil.
267
What is Tolosa-Hunt syndrome (THS)?
An inflammatory condition within the cavernous sinus or superior orbital fissure causing damage to the structures in those regions.
268
What does the internal auditory (or acoustic) meatus transmit?
Facial (CN VII), vestibulocochlear nerves (CN VIII), and the labyrinthine artery.
269
What can damage to the structures within the internal auditory meatus result in?
Deafness and facial muscle paralysis.
270
What are common signs of acoustic neuromas?
Expansion of the internal auditory meatus, deafness, tinnitus, or vertigo.
271
What is the crus cerebri?
The anterior portion of the cerebral peduncle containing the efferent motor tracts.
272
What is the result of damage to the crus cerebri?
Paralysis to a region of the body.
273
What is the function of the tegmentum in the cerebral peduncles?
Coordinates movement.
274
What happens when the tegmentum is damaged?
Results in jerky movements.
275
Where is the supraorbital foramen located?
Under the eyebrow above the orbit.
276
What does the supraorbital foramen transmit?
Supraorbital nerve, artery, and vein.
277
What is the annulus of Zinn?
A ring of fibrous tissue around the optic nerve where it enters at the apex of the orbit.
278
What is the significance of the annulus of Zinn?
It is the origin of several extraocular muscles.
279
What is the lower portion of the annulus of Zinn known as?
The ligament (or tendon) of Zinn.
280
What muscles arise from the lower portion of the annulus of Zinn?
Rectus inferior and part of rectus internus and rectus lateralis.
281
What is the upper portion of the annulus of Zinn known as?
The superior tendon of Lockwood.
282
What muscles arise from the upper portion of the annulus of Zinn?
Rectus superior, rectus medialis, and part of rectus lateralis.
283
A 57 year old women developed signs of ophthalmoplegia, maxillary sensory loss, and a fixed dilated pupil. These signs are most consistent with damage to what structure?
Cavernous sinus
284
What is an electrocardiogram (ECG)?
A non-invasive method of measuring the heart's electrical activity
285
What is the P wave in an ECG?
The first wave that lasts for about 80 ms and is generated by atrial depolarization
286
What does the QRS complex represent in an ECG?
Depolarization of the left and right ventricles
287
Why does the QRS complex display a larger amplitude than the P wave?
The ventricles contain more muscle and generate a more powerful contraction
288
What does the T wave in an ECG indicate?
Recovery (relaxation) of the ventricles
289
Fill in the blank: The first wave in an ECG is called the ______.
P wave
290
True or False: The T wave is associated with atrial depolarization.
False
291
What is the duration of the P wave?
About 80 ms
292
What is an electrocardiogram (ECG)?
A non-invasive method of measuring the heart's electrical activity
293
What is the P wave in an ECG?
The first wave that lasts for about 80 ms and is generated by atrial depolarization
294
What does the QRS complex represent in an ECG?
Depolarization of the left and right ventricles
295
Why does the QRS complex display a larger amplitude than the P wave?
The ventricles contain more muscle and generate a more powerful contraction
296
What does the T wave in an ECG indicate?
Recovery (relaxation) of the ventricles
297
Fill in the blank: The first wave in an ECG is called the ______.
P wave
298
True or False: The T wave is associated with atrial depolarization.
False
299
What is the duration of the P wave?
About 80 ms
300
Which muscle does the trochlear nerve innervate?
Superior oblique muscle
## Footnote
The trochlear nerve innervates the contralateral superior oblique muscle.
301
What are the primary functions of the superior oblique muscle?
Incyclotorsion, depression, abduction
## Footnote
The superior oblique muscle is responsible for incyclotorsion, depression, and abduction of the eye.
302
What is unique about cranial nerve IV in terms of its intracranial course?
It travels the longest intracranial course
## Footnote
Cranial nerve IV (trochlear nerve) has the longest intracranial course compared to all other cranial nerves.
303
What is the size of the trochlear nerve relative to other cranial nerves?
It is the smallest cranial nerve
## Footnote
The trochlear nerve is the smallest of all cranial nerves.
304
Why is the trochlear nerve more prone to damage?
Because it is so thin
## Footnote
The thin structure of the trochlear nerve makes it more susceptible to damage.
305
What condition results from a CN IV palsy?
Hypertropia of the eye on the affected side
## Footnote
A CN IV palsy causes the eye on the affected side to be higher than the other (hypertropia).
306
What visual symptom do patients report with CN IV palsy?
Vertical diplopia that is worse in downgaze and at near
## Footnote
Patients with CN IV palsy experience vertical diplopia, particularly when looking down or at near distances.
307
Which part of the orbit is the weakest?
Orbital floor
308
Which part of the orbit is the thinnest and smallest?
Medial wall
309
Which part of the orbit is the strongest?
Lateral wall
310
311
Drain blood from choroid
Vortex veins
312
Vortex veins drain into the?
Superior and inferior ophthalmic veins
313
What is the difference between pupillary block and plateau iris?
Angle closure is due to pupil dilation causing iris to be pulled centripetally and posteriorly causing increase in iris lens contact in pupillary block
But in plateau iris, angle closure occurs via anteriorly displaced ciliary body or insertion of the iris anteriorly on the ciliary body (central anterior chamber is normal but peripheral anterior chamber is shallow
314
Becker-Shaffer angle grading system
Grade 4: CBB visible
Grade 3: Scleral spur most posterior structure
Grade 2: 1/2 to 1/3 TM is visible (risky to dilate)
Grade 1: only anterior portion of TM is visible or only Schwalbes line is viewed (high risk angle closure)
Grade 0: no structures seen (angle is closed)
*remember most posterior structure is: I Can’t See The Stupid Line: Iris, Ciliary body band, Scleral spur, Trabecular mesh work, Schwalbe’s line
315
What is the first structure observed when evaluating the anterior chamber angle?
Ciliary body
## Footnote
The ciliary body is the starting point for evaluating the anterior chamber angle structures.
316
List the structures of the anterior chamber angle in order from the iris to the anterior.
* Ciliary body
* Scleral spur
* Posterior trabecular meshwork
* Anterior trabecular meshwork
* Schwalbe's line
## Footnote
This sequence outlines the anatomical structures in the anterior chamber angle.
317
What color is the scleral spur typically?
Bright white
## Footnote
The scleral spur's bright white color makes it a reliable landmark during gonioscopy.
318
How does the color of the ciliary body compare to that of the iris?
Typically darker
## Footnote
The pigmentation of the ciliary body can vary based on the iris pigmentation.
319
What is the appearance of the trabecular meshwork?
Greyish or pinkish
## Footnote
The trabecular meshwork is less bright than the scleral spur and its color can vary.
320
Which part of the trabecular meshwork is more pigmented?
Posterior trabecular meshwork
## Footnote
The posterior trabecular meshwork has more pigmentation compared to the anterior trabecular meshwork.
321
What is Schwalbe's line?
Termination of Descemet's membrane
## Footnote
Schwalbe's line is a white ridge and may have pigment on its surface.
322
True or False: The area anterior to Schwalbe's line represents reflections from the surface of the cornea.
True
## Footnote
This reflection is a characteristic observation during gonioscopy.
323
Fill in the blank: The scleral spur is a projection of the _______.
white sclera
## Footnote
The scleral spur serves as a key landmark in gonioscopy.
324
What is the best orientation method when assessing the anterior chamber angle?
Begin with the iris structure and follow it out to the ciliary body
## Footnote
This method helps in accurately identifying the structures in the angle.
325
What may occasionally lie on the surface of Schwalbe's line?
Pigment
## Footnote
The presence of pigment can vary among patients.
326
Uveal tract is comprised of which 3 structures
Iris
Ciliary body
Choroid
