Head and Neck Flashcards
1
Q
State the boundaries of the pharynx
A
base of the skull
inferior border of the cricoid cartilage
2
Q
State the boundaries of the anterior triangle
A
Superior - inferior border of the mandible
Laterally - medial border of SCM
Inferior - sagittal line down midline
3
Q
What is the action of the suprahyoid muscles?
A
elevate the hyoid bone
4
Q
What is the action of the infrahyoid muscles?
A
depress the larynx
5
Q
State the boundaries of the carotid triangle
A
Superior - posterior belly of the digastric muscle
Laterally - medial border of SCM
Inferior - superior belly of the omohyoid
6
Q
What are the contents of the carotid triangle?
A
common carotid artery (which bifurcates here) internal jugular vein hypoglossal nerve vagus nerve carotid sinus
7
Q
State the boundaries of the posterior triangle
A
anterior - posterior border of SCM
posterior - anterior border of the trapezius
8
Q
Between what layers does the superficial cervical fascia lie?
A
dermis
deep cervical fascia
9
Q
What are the contents of the superficial cervical fascia?
A
neurovascular supply to skin superficial veins superficial lymph nodes fat platysma
10
Q
What are the attachments of the platysma?
A
two heads from fascia of the pec major and deltoid
fuse in midline with muscles of the face
11
Q
How is the platysma innervated?
A
cervical branch of the facial nerve
12
Q
What structures are enclosed by the investing layer of deep cervical fascia?
A
SCM
trapezius
submandibular glands
parotid glands
13
Q
What is enclosed by the pretracheal fascia?
A
infrahyoid muscles
thyroid gland
trachea
oesophagus
14
Q
To what structures is the pretracheal fascia attached?
A
carotid sheaths laterally
fibrous pericardium inferiorly
15
Q
What are the contents of the carotid sheath?
A
common carotid artery
internal jugular vein
vagus nerve
deep cervical lymph nodes
16
Q
name the components of the deep cervical fascia
A
investing layer
pretracheal
prevertebral
17
Q
Where does the prevertebral fascia extend to?
A
from the base of the cranium to the third thoracic vertebra inferiorly
as the axillary sheath, surrounding axillary vessels and brachial plexus
18
Q
If an infection occurs between the investing and pretracheal fascia, where can it spread to?
A
thoracic cavity anterior to the pericardium
19
Q
What is the retropharyngeal space?
A
potential space between the prevertebral fascia and the fascia surrounding the pharynx+
20
Q
What complications could an infection in the retropharyngeal space cause?
A
spread of infection to thorax
retropharyngeal abscess - dysphagia and difficulty speaking
21
Q
What are the four muscles of mastication?
A
masseter
temporalis
medial pterygoid
lateral pterygoid
22
Q
How are the muscles of mastication innervated?
A
mandibular nerve
23
Q
What is the actionof the lateral pterygoids?
A
bilateral action - protraction of the mandible
unilateral action - side to side movement of mandible
24
Q
From where do the common carotid arteries arise?
A
Right - bifurcation of the brachiocephalic trunk at the sternoclavicular joint
Left - arch of the aorta
25
Where do the common carotid arteries split?
superior margin of the thyroid cartilage
C4
carotid triangle
26
What is the purpose of carotid sinus massage?
stimulates the baroreceptors
leads to decreased sympathetic activity and increased parasympathetic activity
slows heart rate
27
What nerve transmits information from the carotid sinus to the brain?
glossopharyngeal
28
Where are the baroreceptors located?
carotid sinus at the bifurcation of the common carotid artery
29
What are the carotid bodies?
peripheral chemoreceptors detecting arterial pO2
30
What are the problems involved with carotid sinus hypersensitivity
external pressure on the carotid sinus can cause slowing of heart rate and a decrease in blood pressure
syncope
therefore, do not check pulse in carotid triangle
31
Why does an atheroma often develop at the bifurcation of the common carotid artery?
turbulence of flow
32
`What are the symptoms of a carotid artery atheroma?
What is the cause of these symptoms?
headache
dizziness
muscular weakness
reduced blood flow to the brain
33
What is a possible complication of a carotid artery atheroma?
rupture
embolus
stroke or TIA
34
What is a possible treatment for carotid artery atheroma?
carotid endarterectomy
| atheromatous tunica intima is removed
35
Describe the course of the external carotid artery
travels posterior to the mandibular gland
anterior to the lobule of the ear
ends within the parotid gland
divides into the superficial temporal artery and maxillary artery
36
What are the branches of the external carotid artery?
* Superior thyroid artery
* Lingual artery
* Facial artery
* Ascending pharyngeal artery
* Occipital artery
* Posterior auricular artery
37
Which branch of the external carotid artery supplies the deep structures of the face?
maxillary
38
Where does the internal carotid artery enter the cranial cavity?
the carotid canal in the petrous part of the temporal bone
39
Which arteries supply the scalp?
From the external carotid:
posterior auricular
occipital
superficial temporal
From the internal carotid:
supraorbital
supratrochlear
40
What bones make up the Pterion?
frontal bone
parietal bone
temporal bone
sphenoid bone
41
What is the clinical significance of the pterion?
a fracture at this site can rupture the middle meningeal artery, causing an extradural haematoma - collection of blood between the dura mater and the skull
or haemorrhage
increases intracranial pressure
42
What are the symptoms of an extradural haematoma?
What is the cause of these symptoms?
```
nausea
vomiting
seizures
bradycardia
limb weakness
```
increased intracranial pressure
43
What is the treatment for an extradural haematoma?
diuretics
| drilling burr holes
44
Which arteries of the face are branches of the internal carotid artery?
supraorbital
| supratrochlear
45
Where can the pulse of the facial artery be felt?
inferior border of the mandible anterior to the masseter
46
What is a thyroglossal cyst?
mass in midline of neck
| persistence of thyroglossal duct in the adult
47
Describe the anatomical location of the thyroid
in anterior neck
below thyroid cartilage
C5 to T1
48
Describe the blood supply of the thyroid
paired superior thyroid arteries - first branch of external carotid. supplies superior and anterior gland
paired inferior thyroid arteries - from thyrocervical trunk of subclavian artery. supplies posterior and inferior gland
superior, inferior and middle thyroid veins drain into plexus.
superior and middle to internal jugular.
inferior to brachiocephalic
49
How are the thyroid and recurrent laryngeal nerves related?
the nerves pass underneath the thyroid to the larynx
| damaged in surgery of the thyroid
50
Name the infrahyoid muscles
sternoyhoid
omohyoid
sternothyroid
thyrohyoid
51
Which infrahyoid muscles are in the superficial plane?
sternohyoid
| omohyoid
52
Which infrahyoid muscles are in the deep plane?
sternothyroid
| thyrohyoid
53
How are the superficial infrahyoid muscles innervated?q
anterior rami of C1-C3, carried by the ansa cervicalis
54
Describe the action of the superficial infrahyoid muscles
depress the hyoid bone
55
Describe the attachements of the omohyoid
inferior belly arises from scapuka
moves underneath SCM superomedially
intermediate tendon attached to clavicle
superior belly to hyoid bone
56
Describe the action of the sternothyroid
depresses the thyroid cartilage
57
Describe the innervation of the sternothyroid
anterior rami of C1-C3, carried by the ansa cervicalis
58
Describe the action of the thyrohyoid
depresses the hyoid
| if hyoid fixed, raises larynx
59
Describe the innervation of the thyrohyoid
anterior ramus of C1, carried with hypoglossal nerve
60
Name the parts of the pharynx
nasopharynx
oropharynx
laryngopharynx
61
State the boundaries of the pahrynx
base of the skull
| inferior cricoid cartilage
62
What is the action of the circular muscles of the pharynx
contract sequentially, superior to inferior
constrict the lumen
propel bolus of food inferiorly into oesophagus
63
Name the three circular muscles of the pharynx, and state their location
Superior pharyngeal constrictor - oropharynx
Middle pharyngeal constrictor - laryngopharynx
Inferior pharyngeal constrictor - laryngopharynx
64
Describe the two components of the inferior pharyngeal constrictor
```
superior = thyropharyngeus. oblique fibres
inferior = cricopharyngeus. horixontal fibres
```
65
Describe the action of the longitudinal muscles of the pharynx
shorten and widen the pharynx
| elevate the larynx in swallowing
66
Name the longitudinal muscles of the pharynx
stylopharyngeus
palatopharyngeus
salpingopharyngeus (from Eustachian tube)
67
Describe the innervation of the longitudinal muscles of the pharynx
stylopharyngeus - glossopharyngeal
palatopharyngeus - vagus
salpingopharyngeus - glossopharyngeal
68
Describe the innervation of the circular muscles of the pharynx
vagus nerve
69
describe the sensory innervation of the pharynx
nasopharynx - maxillary nerve CN V V2
oropharynx - glossopharyngeal nerve
laryngopharynx - vagus nerve
70
Describe the blood supply of the pharynx
ascending pharyngeal, lingual, facial and maxillary branches of the external carotid artery
pharyngeal venous plexus to interbal jugular vein
71
State the boundaries of the nasopharynx
Superior - base of the skull
Inferior - soft palate
Anterior - posterior conchae
Posterior - adenoid tonsils
72
Describe the epithelium of the nasopharynx
ciliated pseudostratified columnar epithelium with goblet cells
73
What can recurrent infections of the adenoid tonsils lead to?
adenoids chronically enlarged
obstruction of Eustachian tube
prevention of pressure equalisation and drainage of fluid
chronic otitis media and effusion
74
State the boundaries of the oropharynx
Superior - soft palate
Inferior - superior border of epiglottis
Anterior - oral cavity
Posterior - C2-C3 vertebrae
75
Describe the epithelium of the oropharynx
stratified squamous
76
What structures does the oropharynx contain?
posterior 1/3rd of tongue
lingual tonsils
palatine tonsils
superior pharyngeal constrictor muscle
77
Which lymph nodes are enlarged in tonsillitis?
jugolodigastric
78
What happens if infection spreads from the palatine tonsils to the peritonsillar tissue?
```
abscess
deviation of uvula
quinsy
MEDICAL EMERGENCY
obstruction of pharynx
needs draining and antibiotics
```
79
State the boundaries of the laryngopharynx
Superior - superior border of epiglottis
Inferior - inferior border of the cricoid cartilage
Anterior - larynx
Posterior - C3-C6 vertebrae
80
Describe the epithelium of the laryngopharynx
stratified squamous
81
Where does a pharyngeal diverticulum form?
weak area between the two parts of the inferior pharyngeal constrictor: thyropharyngeus and cricopharyngeus.
= Killian's dehiscence
82
How do the inferior pharyngeal constrictors work together in swallowing?
thyropharngeus contracts
cricopharyngeus relaxes
prevents intrapharyngeal pressure from rising
83
How does a pharyngeal diverticulum form?
no coordinated relaxation of the cricopharyngeus
| high intrapharyngeal pressure
84
What are the symptoms of a pharyngeal diverticulum?
dysphagia
regurgitation
halitosis
85
Describe the phases of swallowing
1. Pushing of food from the oral cavity to the oropharynx
- Tongue and suprahyoid muscles pull the hyoid bone and larynx up
- this is the voluntary phase of the swallowing process
2. The soft palate elevates, closing off the nasopharynx
- This is a reflex-driven process during which the contraction of the suprahyoid muscles and the longitudinal pharyngeal muscles elevate the larynx.
3. The superior constrictors contract
- From now on, the process is automatic
4. The middle and inferior constrictors move the bolus into the laryngopharynx
5. The larynx is protected by the overhanging tongue, epiglottis and vocal cords
6. The cricopharyngeus muscle relaxes; allowing the bolus of food to be propelled into the oesophagus and preventing the intrapharyngeal pressure from rising.
86
Which arteries supplying the neck arise from the subclavian artery?
vertebral
internal thoracic
thyrocervical trunk
87
Which arteries arise from the thyrocervical trunk?
inferior thyroid -> ascending cervical artery
transverse cervical artery
suprascapular artety
88
Through what foramina do the vertebral arteries enter the cranial cavity?
foramen magnum
89
The vertebral arteries converge to form the:
Supplying the:
basilar arteries
brain
90
Which veins unite to form the angular vein?
| Where?
supraorbital and supratrochlear
| medial angle of the eye
91
How are the veins of the scalp connected to the dural venous sinuses?
emissary veins
connect to diploic veins
connect to dural venous sinuses
92
What are dural venous sinuses?
space between periosteal and meningeal layers of the dura mater
lined by endothelial cells
collect venous blood
drain into the internal jugular veins
93
What is the cavernous sinus?
a dural venous sinus
plexus if veins on the upper surface of the sphenoid
receives blood from ophthalmic veins, cerebral veins and sphenopalatine sinus
94
What is the danger triangle?
deep facial veins drain into the pterygoid venous plexus, which drains into the cavernous sinus
Facial vein is connected to the cavernous sinus by the superior ophthalmic vein
Veins are valveless
infection can spread from the face to the venous sinuses
95
What structures are located within the cavernous sinus?
```
internal carotid artery
abducens nerve
occulomotor nerve
trochlear nerve
ophthalmic nerve (V2)
maxillary nerve (V3)
```
96
Describe the course of the external jugular vein
posterior auricular and retromandibular veins converge posterior to the angle of the mandible, inferior to the outer ear
descends within the superficial fascia anterior to SCM
receives posterior external jugular, transverse cervical and suprascapular veins
crosses SCM in an oblique, posterior and inferior direction
passes under clavicle and drains into subclavian
97
What are the clinical consequences if the external jugular vein is severed?
```
lumen held open by investing fascia
air drawn into vein
cyanosis
blood flow though right atrium stopped
MEDICAL EMERGENCY
```
98
How is a severed external jugular vein managed?
pressure to wound
99
Describe the course of the internal jugular vein
continutaiton of sigmoid sinus
exits skull via jugular foramen
descends within the carotid sheath deep to the sternocleidomastoid lateral to common carotid artery
receives blood from the facial, lingual, occipital and superior and middle thyroid veins
combines with subclavian vein to form brachiocephalic vein posterior to sternal end of clavicle
100
Which of the blood vessels within the carotid sheath is more lateral?
internal jugular vein is lateral to the common carotid artery
101
Why do injuries to the scalp bleed profusely?
artery walls are tightly bound to connective tissue of the scalp. prevents constriction
anasatamoses mean the scalp is densely vascularised
if the epicranial aponeurosis is severed, the occipital and frontalis muscles pull from opposite ends
102
Describe the blood supply of the skull
middle meningeal artery
103
What does the JVP tell us?
An estimation of the right atrial pressure
104
How is the JVP measured?
patient lies at 45 degrees
| height of pulsation measured from 5cm above sternal angle
105
How is the flow of lymph within the lymphatic system ensured?
passive constriction by skeletal muscles
| intrinsic constriction of smooth muscle cells
106
Describe the route of fluid from tissue fluid to lymphatic duct
```
Tissue fluid
Lymphatic capillary
• The fluid becomes lymph here
Lymphatic vessels – afferent
• Multiple afferent vessels drain into one lymph node
Lymph node
Lymphatic vessel – efferent
Lymphatic trunk
Lymphatic duct
```
107
Where do the lymphatic ducts drain into?
subclavian veins
Right lymphatic duct into right subclavian vein
thoracic duct into left subclavian vein
108
What regions of the body drain into the right lymphatic duct?
Right side of head, neck, arm and thorax
109
What are lymph nodes?
connective tissue structures
reticular inside - physical filter
tough fibrous outer capsule
110
Describe the immune function of lymph nodes
phagocytes act as phagocytic filter
| lymphocytes for immune surveillance, allowing body to mount appropriate response
111
What is a superficial lymph node?
drains a specific area. in superficial cervical fascia
112
What is a deep lymph node?
receives drainage from superficial lymph nodes. deep to the investing layer of deep cervical fascia, mostly within the carotid sheath
113
What drains into the submandibular lymph nodes?
```
upper lip and teeth
lateral part of lower lip
most of face
anterior nasal cavity
cheeks
middle tongue
submandibular gland
sublingual gland
```
114
What drains into the submental lymph nodes?
lower lip/teeth
anterior chin
tip of tongue
floor of mouth
115
What drains into the anterior and posterior superficial cervical lymph nodes?
skin of neck
116
What drains into the pre auricular lymph nodes?
middle-posterior scalp
skin of lateral ear
parotid gland
117
What drains into the post auricular lymph nodes?
posterior scalp
cranial surface of pinna
back of external acoustic meatus
118
What drains into the occipital lymph nodes?
posterior scalp and neck
119
What will an infected swollen lymph node feel like?
tender
firm
mobile
120
What will an metastatic swollen lymph node feel like?
hard
matted
non-tender
121
What drains into the jugulodigastric lymph nodes?
palatine tonsil
| posterior 1/3rd of tongue
122
What drains into the juguloomohyoid lymph nodes?
```
tongue
oral cavity
trachea
larynx
oesophagus
thyroid gland
```
123
Name the superficial lymph nodes
```
submental
submandibular
pre auricular
post auricular
occipital
posterior cervical
anterior cervical
```
124
Name the deep lymph nodes
jugulo digastric
jugulo omohyoid
supraclavicular
125
What is the significance of Virchow's node
left supraclavicular
drainage from abdominal cavity
enlarged indicates cancer in abdomen - esp gastric
126
What is lymphoedema?
fluid retention and tissue swelling due to a compromised immune system
127
What is lymphoedema caused by?
```
removal or enlargement of lymph nodes
infection
damage to system
immobility
congenital problems
```
128
Describe the frontal bone
forms anterior part of the skull
upper border of occipital margins
contains frontal sinus
forms roof of orbit
129
Describe the parietal bone
forms side and roof of cranial cavity
130
Name the 6 parts of the temporal bone
```
squamous
mastoid
tympanic
styloid process
zygomatic process
petrous part
```
131
Which bone contains the foramen magnum?
occipital
132
What are some key features of the ethmoid bone?
cribiform plate
crista galli
ethmoid bulla
air cells
133
What is an ethmoid fracture likely to cause?
anosmia
134
Describe the mandible
two separate bones combine in the midline - mental symphysis
135
Where is the coronal suture found?
anterior from left to right
136
Where is the sagittal suture found?
midline from front to back
137
Where is the lambdoidal suture found?
posterior from left to right
138
Where is bregma found?
anterior
| between coronal and sagittal sutures
139
Where is lamda found?
posterior
| between sagittal and lambdoidal sutures
140
In a baby, what are the precursors of bregma and lambda?
anterior and posterior fontanelles
141
How is a newborn baby's skull different to the skull of an adult?
wide cranial sutures
| held together by connective tissue that allows for movement
142
During labour, how does the baby's skull change?
cranial bones pushed together
serrated bone edges interlock
protects the brain from injury
143
Why does a pre-term labour have an increased risk of brain damage for the fetus?
cranial sutures are too wide to interlock
| brain not protected
144
define skull
cranium and mandible
145
define cranium
superior aspect of the skull
146
What features allow the cervical vertebrae to be identified?
triangular vertebral foramen
bifid spinous process
transverse foramina = holes in transverse process for vertebral artery, vein and sympathetic nerves
147
Describe the atlas
C1
no vertebral body
no spinous process
articular facet anteriorly for articulation with dens of axis
lateral masses for transverse ligament of atlas
superior articular surface on later mass for occipital condyle
groove on posterior arch for vertebral artery and C1
148
describe the axis
C2
| dens extends superiorly form anterior portion
149
Where are the atlanto-occipital joints found?
What movement of the head do these joints allow?
superior facets of lateral masses of the atlas
occipital condyles of base of cranium
flexion of the head
150
Where are the atlanto-axial joints found?
What movement of the head do these joints allow?
```
lateral:
inferior facets of lateral masses of C1
superior facets of C2
Medial:
articular facet C1
dens
```
rotation of the head
151
What are common signs and symptoms of a skull fracture?
```
bleeding
clear fluid draining from ears and nose
poor balance
confusion
slurred speech
stiff neck
```
152
What bones form the anterior cranial fossa?
frontal, ethmoid and sphenoid bones
153
What bones form the posterior cranial fossa?
occipital bone and temporal bones
154
What bones form the middle cranial fossa?
sphenoid, temporal
155
Describe a depression fracture
fracture of skull
depression of bone inwards
result of a direct blow
156
What are the possible consequences of a depression fracture?
skull indentation
| brain injury
157
Describe a linear fracture of the skull
simple break in the bone traversing its full thickness
| radiating (stellate) fracture lines away from the point of impact
158
State the boundaries of the anterior cranial fossa
Anteriorly and laterally - inner surface of the frontal bone.
Posteriorly and medially - limbus of the sphenoid bone.
Posteriorly and laterally - lesser wings of the sphenoid bone
Floor - frontal bone, ethmoid bone and the anterior aspects of the body and lesser wings of the sphenoid bone
159
State the boundaries of the middle cranial fossa
Anteriorly and laterally - lesser wings of the sphenoid bone.
Anteriorly and medially - limbus of the sphenoid bone.
Posteriorly and laterally - superior border of the petrous part of the temporal bone.
Posteriorly and medially - dorsum sellae of the sphenoid bone
Floor - body and greater wing of the sphenoid, and the squamous and petrous parts of the temporal bone
160
State the boundaries of the posterior cranial fossa
Anteriorly and medially - dorsum sellae of the sphenoid bone
Anteriorly and laterally - superior border of the petrous part of the temporal bone
Posteriorly - internal surface of the squamous part of the occipital bone
Floor - mastoid part of the temporal bone and the squamous, condylar and basilar parts of the occipital bone
161
Where is the cribriform plate found?
ethmoid bone
| either side of crista galli
162
What passes through the cribriform plate?
olfactory nerve fibres CN I
163
Where are the optic canals found?
anteriorly on the sphenoid bone
connected by chiasmatic sulcus
route from middle cranial fossa into orbital cavities
164
What passes through the optic canals?
the optic nerves (CN II)
| ophthalmic arteries
165
Where are the superior orbital fissures found?
anteriorly in the sphenoid bone
lateral to the optic canals
route from middle cranial fossa into orbit
166
What passes through the superior orbital fissure?
```
oculomotor nerve (CN III)
trochlear nerve (CN IV)
opthalmic branch of the trigeminal nerve (CN V1)
abducens nerve (CN VI)
opthalmic veins
sympathetic fibres
```
167
Where are the foramen rotundum found?
anteriorly in the sphenoid bone
posterior to the superior orbital fissure
route from middle cranial fossa into pterygopalatine fossa
168
What passes through the foramen rotundum?
maxillary branch of the trigeminal nerve (CN V2)
169
Where are the foramen ovale found?
posterior part of the sphenoid bone
posterior to foramen rotundum
medial to foramen spinosum
route from middle cranial fossa to infratemporal fossa
170
What passes through the foramen ovale?
mandibular branch of the trigeminal nerve (CN V3)
| accessory meningeal artery
171
Where are the foramen spinosum found?
posterior part of the sphenoid bone
lateral to foramen spinosum
route from middle cranial fossa to infratemporal fossa
172
What passes through the foramen spinosum?
middle meningeal artery
middle meningeal vein
meningeal branch of CN V3
173
Where is the carotid canal found?
in the temporal bone
| posterior and medial to the foramen ovale
174
What passes through the carotid canal?
internal carotid artery
| deep petrosal nerve
175
Where is the internal acoustic meatus found?
posterior aspect of the petrous part of the temporal bone.
176
What passes through the internal acoustic meatus?
```
facial nerve (CN VII)
vestibulocochlear nerve (CN VIII)
labrynthine artery
```
177
Where is the foramen magnum found?
occipital bone
centrally in the floor of the posterior cranial fossa
largest foramen in the skull
178
What passes through the foramen magnum?
```
the medulla of the brain
meninges
vertebral arteries
spinal accessory nerve (ascending)
dural veins
anterior and posterior spinal arteries
```
179
Where are the jugular foramina found?
occipital bone
| either side of the foramen magnum
180
What passes through the jugular foramina?
```
glossopharyngeal nerve
vagus nerve
spinal accessory nerve (descending)
internal jugular vein
inferior petrosal sinus
sigmoid sinus
meningeal branches of the ascending pharyngeal and occipital arteries
```
181
Describe a basal skull fracture
Affects the base of the skull
182
How does a basal skull fracture present?
bruising behind the ears = Battle’s sign (mastoid ecchymosis)
bruising around the eyes/orbits = Raccoon eye’s
183
What is a diastatic skull fracture?
occurs along a suture line
causes a widening of the suture
most often seen in children
184
Describe a Jefferson Fracture
compression of the lateral masses of the atlas (C1) between the occipital condyles and the axis
they are driven apart, fracturing one or both of the anterior/posterior arches.
185
How does a patient get a Jefferson Fracture?
vertical fall onto an extended neck e.g. diving into excessively shallow water
186
Does a Jefferson Fracture damage the spinal cord?
Since the vertebral foramen is large, it is unlikely that there will be damage to the spinal cord at the C1 level. However, there may be damage further down the vertebral column
187
What is a Hangman's Fracture?
fracture of the pars interarticularis, the bony column between the superior and inferior articular facets of the axis.
188
What are the consequences of a Hangman's Fracture?
injury is likely to be lethal
the fracture fragments or the force involved are likely to rupture the spinal cord
causing deep unconsciousness, respiratory and cardiac failure, and death
189
How does a fracture of the dens occur?
traffic collisions and falls
190
What are the consequences of a fractured dens?
fractures are unstable
high risk of avascular necrosis, due to the isolation of the distal fragment from any blood supply
fractures of the dens often take a long time to heal.
risk of spinal cord involvement.
191
What causes a Whiplash Injury?
Hyperextension
| head being whipped back on the shoulders
192
What are the consequences of whiplash?
minor cases:
anterior longitudinal ligament of the spine is damaged which is acutely painful for the patient.
severe cases:
fractures can occur to any of the cervical vertebrae as they are suddenly compressed by rapid deceleration
worst-case scenario:
dislocation or subluxation of the cervical vertebrae
This often happens at the C2 level, where the body of C2 moves anteriorly with respect to C3.
spinal cord involvement, and as a consequence quadraplegia or death may occur.
More commonly, subluxation occurs at the C6/C7 level (50% of cases).
193
Describe the location of the larynx
```
in anterior compartment of neck
suspended from the hyoid
C3-C6
opens superiorly into laryngopharynx
opens inferiorly into trachea
```
194
How can the larynx be divided into sections?
Supraglottis
Glottis
Subglottis
195
State the boundaries of the supraglottis
inferior surface of the epiglottis
| vestibular folds
196
State the boundaries of the glottis
vocal cords
| 1cm below
197
State the boundaries of the subglottis
inferior border of the glottis
| inferior border of the cricoid cartilage
198
Name the cartilages that combine to form the larynx
```
epiglottis
thyroid
cricoid
arytenoid x2
corniculate x2
cuneiform x2
```
199
Describe the cricoid cartilage
complete ring
| broader posteriorly
200
What type of cartilage is the epiglottis?
elastic
201
Describe the arytenoid cartilages
pyramidal
sit on the cricoid
articulate with conrniculate cartilage superiorly
vocal process anteriorly - vocal ligament attaches
muscular process posteriorly - attachment for the posterior and lateral cricoarytenoid muscles
202
How can the muscles of the larynx be grouped?
intrinsic
| extrinsic
203
Describe the action of the external laryngeal muscles
elevate or depress the larynx during swallowing
204
Describe the action of the internal laryngeal muscles
move the components of the larynx
control the shape of the rima glottidis
control length and tension of the vocal folds
205
What muscles is the external laryngeal group of muscles composed of?
suprahyoid
infrahyoid
stylopharyngeus
206
How are the internal laryngeal muscles innervated?
inferior laryngeal nerve - terminal branch of the recurrent laryngeal nerve - vagus nerve
207
How is the cricothyroid innervated?
external branch of the superior laryngeal nerve - vagus nerve
208
What is the action of the cricothyroid?
tilts the thyroid forward to help tense the vocal cords
209
Describe the histology of the vocal folds from superficial to deep
* Non-keratinised stratified squamous epithelium
* Reinke’s space – This watery, amorphous layer is rich in glycosaminoglycans. Due to its fluidity, the epithelium is able to vibrate freely above it to create sound.
* Vocal ligament
* Vocalis muscle
210
Describe the arterial blood supply to the larynx
What is the course of these vessels?
Superior laryngeal artery – a branch of the superior thyroid artery (derived from the external carotid). It follows the internal branch of the superior laryngeal nerve into the larynx.
• Inferior laryngeal artery – a branch of the inferior thyroid artery (derived from the thyrocervical trunk). It follows the recurrent laryngeal nerve into the larynx.
211
Describe the venous drainage of the larynx
The superior laryngeal vein - drains to the superior thyroid then the internal jugular vein
the inferior laryngeal vein - drains to the inferior thyroid vein then the left brachiocephalic vein
212
Describe the sensory innervation of the larynx
supraglottis - superior laryngeal nerve
| infraglottis - recurrent laryngeal nerve
213
In full bilateral palsy of the vocal folds, what are the clinical consequences?
both folds paralysed between adduction and abduction
breathing impaired
no phonation possible
214
In partial bilateral palsy of the vocal folds, what are the clinical consequences?
vocal folds paralysed in fully adducted position
airway obstruction
MEDICAL EMERGENCY
215
What is a cricothyroidectomy?
an emergency procedure to provide a temporary airway used in situations where there is an obstruction at or above the larynx
To perform the technique, the thyroid cartilage is palpated in the neck – below which there is a depression representing the cricothyroid ligament. A small incision is made in the midline of this ligament, and an endotracheal tube is inserted to secure the airway.
216
What type of cancer are most laryngeal cancers?
squamous cell carcinomas
217
Which area of the larynx is most affected by laryngeal cancer?
glottis
218
State some of the risk factors of laryngeal cancer
smoking
alcohol
occupational exposures (asbestos, formaldehyde, nickel, isopropyl alcohol and sulphuric acid mist)
insufficient fruit and vegetables intake
HPV16 seropositivity.
219
What are the symptoms of laryngeal cancer?
```
Chronic hoarseness
pain
dysphagia
a lump in the neck
earache
persistent cough
```
Patients may also describe breathlessness, aspiration, haemoptysis, fatigue and weakness, or weight loss
220
Why can epiglottitis be life threatening?
swelling
| complete obstruction of the airway
221
What age group is epiglottis most common in?
2-5 years
| immunocompromised adults in their 40s and 50s
222
What are the symptoms of epiglottitis?
Sore throat.
Odynophagia (painful swallowing).
Inability to swallow secretions (drooling in children).
Muffled voice - 'hot potato' voice.
Fever
The 'tripod sign' - the patient leans forward on outstretched arms to move inflamed structures forward, thereby easing the upper airway obstruction
Stridor
223
What is the cause of croup?
viral URTI
224
Describe the pathophysiology of croup
Viral URTI causes nasopharyngeal inflammation that may spread to the larynx and trachea
subglottal inflammation, oedema and compromise of the airway at its narrowest portion occurs
movement of the vocal cords is impaired leading to the characteristic cough
225
What age group is croup most common in?
children aged 6 months to 3 years, with a peak incidence during the second year of life
226
What are the symptoms of croup?
runny nose, sore throat, fever and cough.
progresses over the course of a couple of days to include the characteristic barking cough and hoarseness.
Stridor (harsh, low-pitched noise heard during inspiration) may be heard at rest or only when the child is agitated or active.
Chest sounds are usually normal but can be decreased in volume where there is severe airflow limitation.
227
What is laryngomalacia?
congenital laryngeal abnormality
larynx is soft and floppy - abnormal cartilages
collapses during breathing
228
What are the symptoms of laryngomalacia?
noisy respiration
inspiratory stridor
normal cry
229
How is laryngomalacia treated?
conservative management
| 99% of cases resolve by 18-24 months
230
Where is the infratemporal fossa found?
below the middle cranial fossa
| deep to the masseter and zygomatic arch
231
What shape is the infratemporal fossa?
wedge
232
Which spaces does the infratemporal fossa communicate with?
pterygopalatine fossa by the pterygomaxillary fissure
| temporal fossa superiorly
233
State the boundaries of the infratemporal fossa
* Lateral – ramus of the mandible.
* Medial – lateral pterygoid plate of the sphenoid.
* Anterior – posterior surface of the maxilla.
* Posterior – carotid sheath.
* Floor - medial pterygoid muscle
* Roof - greater wing of the sphenoid bone
234
How is the infratemporal fossa connected to the cranial cavity?
foramen ovale
| foramen spinosum
235
What are the contents of the infratemporal fossa?
```
medial pterygoids
lateral pterygoids
mandibular nerve V3
chorda tympani
otic ganglion
maxillary artery -> middle meningeal artery
pterygoid venous plexus
```
236
How does the middle meningeal artery reach the cranial cavity?
maxillary artery in infratemporal fossa becomes middle meningeal artery
foramen spinosum to cranial cavity
237
What branches of the mandibular nerve begin in the infratemporal fossa?
auricotemporal
buccal
lingual
inferior alveolar
238
How does the mandibular nerve enter the infratemporal fossa?
foramen ovale
239
What is the process of and result of a mandibular nerve block?
anaesthetic injection in infratemporal fossa
| affects inferior alveolar, lingual, buccal and auricotemporal nerves
240
What is the process of and result of an inferior alveolar nerve block?
Within the mandibular canal, the inferior alveolar nerve forms the inferior dental plexus
A major branch of this plexus, the mental nerve, supplies the skin and mucous membranes of the lower lip, skin of the chin, and the gingiva of the lower teeth.
The anaesthetic is administered at the mandibular foramen
The anaesthetic fluid also spreads to the lingual nerve which originates near the inferior alveolar nerve, causing numbness of the anterior 2/3 of the tongue.
241
Name the articulating surfaces of the TMJ
mandibular fossa of the temporal bone
articular tubercle of temporal bone
head of mandible
covered by fibrocartilage NOT HYALINE
242
What separates the articular surfaces of the TMJ?
articular disk
243
Describe the articular disk of the TMJ
upper surface = concavoconvex
lower surface = concave
thinner in the middle
244
Name the extracapsular ligaments of the TMJ
Temporomandibular ligament
Sphenomandibular ligament
Stylomandibular ligament
245
What is the function of the temporomandibular ligament
lies laterally and runs from the lower border of the zygomatic process to the mandibular neck.
acts to prevent posterior dislocation of the joint
246
What is the function of the sphenomandibular ligament
Remains at a constant length and tension for all positions of the mandible, preventing inferior dislocation.
247
What is the function of the stylomandibular ligament
extends from the styloid process to the posterior ramus of the mandible.
A thickening of the deep fascia of the parotid gland, separating the parotid and submandibular glands.
Along with the facial muscles, it supports the weight of the jaw.
248
What is posterior displacement of the mandible at the TMJ limited by?
the postglenoid tubercle
| temporomandibular ligament
249
What is anterior displacement of the mandible at the TMJ limited by?
the articular tubercle
250
What is inferior displacement of the mandible at the TMJ limited by?
spenomandibular ligament
| stylomandinular ligament
251
What muscles perform retraction of the mandible?
geniohyoid
| digastric
252
What muscles perform protrusion of the mandible?
lateral pterygoid
| medial pterygoid
253
What movements does the upper part of the TMJ allow?
translational movements
= protrusion
= retraction
254
What movements does the lower part of the TMJ allow?
rotational movements
= elevation
= depression
255
What muscles perform elevation of the mandible?
temporalis
masseter
medial pterygoid
256
What muscles perform depression of the mandible?
```
mostly produced by gravity
digastric
omohyoid
geniohyoid
mylohyoid
```
257
What movements produce opening of the mouth?
protrusion
| depression
258
What movements produce closing of the mouth?
retraction
| elevation
259
What causes dislocation of the TMJ?
blow to side of face
yawning
taking a large bite
mandibular head slips out of the mandibular fossa anteriorly
260
What is a collection of cell bodies called in the CNS?
nucleus
261
What is a collection of cell bodies called in the PNS?
ganglion
262
Name the cranial nerves
```
olfactory
optic
occulomotor
trochlear
trigeminal
abducens
facial
vestibulocochlear
glossopharyngeal
vagus
accessory
hypoglossal
```
263
Where do cranial nerves III and IV originate from?
midbrain
264
Where do cranial nerves V to VIII originate from?
pons
265
Where do cranial nerves IX to XII originate from?
medulla oblongata
266
What is the function of CN I?
special sensory
| smell
267
What is unique about CN I and CN II?
brain tracts
| surrounded by cranial meninges
268
Describe the course of CN I
olfactory receptor neurons in olfactory mucosa
ascends through cribriform plate of ethmoid to form olfactory bulb, which lies in the olfactory groove
then reaches the olfactory tract
269
Which foramina does CN I pass through?
cribriform plate
270
What is the function of CN II?
special sensory
| sight
271
Describe the course of CN II
Starts at retina
| continues to the optic tract and then the primary visual cortex (in the occipital lobes)
272
Which foramina does CN II pass through?
optic canal
273
What is the function of CN III?
motor
superior and inferior rectus, medial rectus, inferior oblique and levator palaebae superioris
Carries parasympathetic fibres to sphincter pupillae and ciliary muscles
274
Describe the course of CN III
Starts in the oculomotor nucleus of the midbrain
enters lateral aspect of the cavernous sinus
travels through the superior orbital fissure
splits to form a superior and inferior division
parasympathetic fibres travel with inferior division
275
Which foramina does CN III pass through?
superior orbital fissure
276
State causes of an occulomotor nerve lesion
Increasing intracranial pressure – compresses the nerve against the temporal bone.
Aneurysm of the posterior cerebral artery.
Cavernous sinus infection or trauma.
diabetes
multiple sclerosis
myasthenia gravis
giant cell arteritis.
277
What are the clinical signs associated with an occulomotor nerve lesion?
Ptosis (drooping upper eyelid) – due to paralysis of the levator palpabrae superioris.
Eyeball resting in the ‘down and out‘ location – due to the paralysis of the superior, inferior and medial rectus, and the inferior oblique. The patient is unable to elevate, depress or adduct the eye.
Dilated pupil = mydriasis due to the unopposed action of the dilator pupillae muscle
278
What is the function of CN IV?
motor
| superior oblique - moves eye down and in
279
Describe the course of CN IV
Starts in the trochlear nucleus of the dorsal midbrain
runs anteriorly and inferiorly within the subarachnoid space before piercing the dura mater adjacent to the posterior clinoid process of the sphenoid bone.
Moves along the lateral wall of the cavernous sinus which contains the:
enters the orbit of the eye
280
Which foramina does CN IV pass through?
superior orbital fissure
281
What are the causes of trochlear nerve palsy?
congenital fourth nerve palsy
diabetic neuropathy
thrombophlebitis of cavernous sinus
raised intracranial pressure
282
What are the symptoms of trochlear nerve palsy?
diplopia when looking down and in
| subtle head tilt
283
What is the function of CN V?
Motor
medial pterygoid, lateral pterygoid, masseter, temporalis
Sensory
skin, mucous membranes and sinuses of the face
284
Describe the course of CN V
Starts in the trigeminal sensory nuclei within the pons which then forms a sensory root.
In the middle cranial fossa, the sensory root expands into the trigeminal ganglion, located lateral to the cavernous sinus, in a depression of the temporal bone = the trigeminal cave.
the trigeminal ganglion gives rise to 3 divisions: ophthalmic (V1), maxillary (V2) and mandibular (V3).
The ophthalmic nerve and maxillary nerve travel lateral to the cavernous sinus exiting the cranium via the superior orbital fissure and foramen rotundum respectively.
The mandibular nerve exits via the foramen ovale entering the infra-temporal fossa.
The motor root passes inferiorly to the sensory root, along the floor of the trigeminal cave. Its fibres are only distributed to the mandibular division.
285
Which foramina does CN V pass through?
ophthalmic - superior orbital fissure
maxillary - foramen rotundum
mandibular - foramen ovale
286
How is the motor function of the trigeminal nerve tested?
ask the patient to clench their jaw
palpate superior to the zygomatic arch to feel for contraction of the temporalis repeat palpating inferiorly for the masseter.
Ask the patient to open their mouth and deviate their mandible to the right and left to check for competence of the medial and lateral pterygoid muscles
287
What is the function of CN VI?
Motor
| lateral rectus - lateral eye movement
288
Describe the course of CN VI
Starts in the abducens nucleus in the pons
enters the subarachnoid space and pierces the dura mater to run in a space known as Dorello’s canal.
The nerve travels through the cavernous sinus entering the orbit of the eye through the superior orbital fissure.
289
Which foramina does CN VI pass through?
Superior orbital fissure
290
What causes palsy of the abducens nerve?
downward pressure on the brainstem (e.g. brain tumour, extradural haematoma)
Wernicke-Korsakoff syndrome (caused by thiamine deficiency and generally seen in alcoholics) is a rare cause of sixth nerve palsy.
diabetic neuropathy and thrombophlebitis of the cavernous sinus
291
What are the signs and symptoms of abducens nerve palsy?
diplopia
medially rotated eye which cannot be abducted past the midline
rotating the head to allow the eye to look sideways
292
What is the function of CN VII?
Special sensory
taste to anterior 2/3rds of tongue
Motor
frontalis, orbicularis occuli, orbicularis oris, buccinators, zygomaticus, mentalis, platysma, stapedius
293
Describe the course of CN VII
the sensory and motor roots originate in the pons and then travel through the internal acoustic meatus, a 1cm long opening in the petrous part of the temporal bone.
within the temporal bone, the roots leave the internal acoustic meatus, and enter into the Z shaped facial canal
Within the canal, the two roots fuse to form the facial nerve.
The nerve gives rise to the greater petrosal nerve (parasympathetic fibres to glands), the nerve to stapedius (motor fibres to stapedius muscle), and the chorda tympani (special sensory fibres to the anterior 2/3 tongue) within the facial canal
the nerve exits the facial canal via the stylomastoid foramen as the facial nerve, located just posterior to the styloid process of the temporal bone.
Between the stylomastoid foramen, and the parotid gland, three more motor branches
Within the parotid gland, the nerve terminates by splitting into its five branches.
294
Which branches of the facial nerve are given off before it passes through the stylomastoid foramen?
greater petrosal nerve - parasympathetic fibres to glands,
nerve to stapedius - motor fibres to stapedius muscle chorda tympani - special sensory fibres to the anterior 2/3 tongue
295
Which foramina does CN VII pass through?
exits cranium via internal acoustic meatus
exits facial canal via stylomastoid foramen
296
What are the names of the motor branches of the facial nerve?
```
temporal
zygomatic
buccal
mandibular
cervical
```
297
Where do intracranial lesions of the facial nerve occur?
proximal to the stylomastoid foramen
298
Where do extracranial lesions of the facial nerve occur?
distal to the stylomastoid foramen
299
What are some causes of intracranial lesions of the facial nerve?
middle ear pathology - tumour or infection
| Bell’s palsy
300
What are some causes of extracranial lesions of the facial nerve?
Parotid gland pathology – e.g a tumour, parotitis, surgery.
Infection of the nerve – particularly by the herpes virus.
Compression during forceps delivery – the neonatal mastoid process is not fully developed, and does not provide complete protection of the nerve.
Idiopathic – If no definitive cause can be found, the disease is termed Bell’s palsy.
301
How is examination of the motor facial nerve carried out?
look for symmetry of face
```
Ask patient to:
raise eyebrows
close eyes tightly
blow out their cheeks
smile
```
302
What is the function of CN VIII?
```
Special Sensory
from cochlea (hearing) and semicircular canals (balance)
```
303
Describe the course of CN VIII
Originates in the cerebellopontine angle
| splits into the vestibular nerve and cochlear nerve to innervate the semicircular canals and cochlea in the inner ear
304
Which foramina does CN VIII pass through?
internal acoustic meatus
305
What is a vestibular schwannoma?
What does this cause?
benign overgrowth of schwann cells of vestibulocochlear nerve
leading to compression of the facial nerve
306
What are the symptoms of vestibular neuritis?
Vertigo – a false sensation that oneself or the surroundings are spinning or moving.
Nystagmus – a repetitive, involuntary to-and-fro oscillation of the eyes.
Loss of equilibrium (especially in low light).
Nausea and vomiting.
307
What are the symptoms of labyrinthitis?
Vertigo – a false sensation that oneself or the surroundings are spinning or moving.
Nystagmus – a repetitive, involuntary to-and-fro oscillation of the eyes.
Loss of equilibrium (especially in low light).
Nausea and vomiting
sensorineural hearing loss
tinnitus
308
What is the function of CN IX?
Sensory
oropharynx, posterior 1/3rd of the tongue, carotid sinus and body
Motor
stylopharyngeus
309
Describe the course of CN IX
Originates in the medulla oblongata and continues through the jugular foramen and down the neck to innervate the tongue, parotid, carotid and stylopharyngeus
310
Which foramina does CN IX pass through?
jugular foramen
311
How is the glossopharyngeal nerve part of the gag reflex?
sensory innervation of oropharynx
| afferent branch of gag reflex
312
What is the function of CN X?
sensory
laryngopharynx
external acoustic meatus
motor
muscles of pharynx and larynx
313
Describe the course of CN X
Originates in the medulla and continues through the jugular foramen
travels in carotid sheath
Left and right asymmetry – recurrent laryngeal nerves
oesophageal plexus
314
Which foramina does CN X pass through?
jugular foramen
315
What are the signs of vagus nerve lesion in the oropharynx?
palatoglossal arch drops
| uvula deviates away from affected side
316
How is the vagus nerve part of the gag reflex?
motor efferents
317
What is the function of CN XI?
motor
| sternocleidomastoid and trapezius
318
Describe the course of CN XI
Originate at spinal nerve roots C1-C5
travels through the foramen magnum to enter cranial cavity
then the jugular foramen to exit cranial cavity
travels along the internal carotid artery to the SCM and the trapezius.
319
Which foramina does CN XI pass through?
foramen magnum to enter cranial cavity
jugular foramen to exit cranial cavity
320
What are the causes of accessory nerve palsy?
iatrogenic - cervical lymph node biopsy or cannulation of the internal jugular vein
321
What is the function of CN XII?
motor
| extrinsic and intrinsic movement of the tongue
322
Describe the course of CN XII
o Originates in the hypoglossal nucleus in the medulla
| Travels through the hypoglossal canal to the tongue
323
Which foramina does CN XII pass through?
Hypoglossal canal
324
What are the causes of hypoglossal nerve palsy?
tumours
| penetrating traumatic injuries. dissection of the internal carotid artery
325
What are the signs of a hypoglossal nerve palsy?
deviation of the tongue towards the damaged side on protrusion,
muscle wasting and fasciculations on the affected side
326
Which muscles does the superior branch of the occulomotor nerve supply?
superior rectus
| levator palpabrae superioris
327
Which muscles does the inferior branch of the occulomotor nerve supply?
inferior rectus
medial rectus
inferior oblique
328
What are the terminal branches of the ophthalmic nerve?
frontal
lacrimal
nasociliary
329
What are the structures innervated by the ophthalmic nerve derived from?
FNP
330
What are the structures innervated by the maxillary nerve derived from?
maxillary prominence of the 1st pharyngeal arch
331
What are the terminal branches of the mandibular nerve?
buccal nerve
inferior alveolar nerve
auricotemporal nerve
lingual nerve
332
Which embryological structure is associated with the facial nerve?
second pharyngeal arch
333
Which embryological structure is associated with the trigeminal nerve?
first pharyngeal arch
334
What branches of the facial nerve arise between the stylomastoid foramen and the parotid gland?
Posterior auricular nerve – Ascends in front of the mastoid process, and innervates the intrinsic and extrinsic muscles of the outer ear. It also supplies the occipital part of the occipitofrontalis muscle.
Nerve to the posterior belly of the digastric muscle – responsible for raising the hyoid bone.
Nerve to the stylohyoid muscle – responsible for raising the hyoid bone
335
Which muscles does the temporal branch of the facial nerve innervate?
frontalis
| orbicularis oculi
336
Which muscles does the zygomatic branch of the facial nerve innervate?
orbicularis oculi.
337
Which muscles does the buccal branch of the facial nerve innervate?
orbicularis oris
| buccinator
338
Which muscles does the mandibular branch of the facial nerve innervate?
mentalis
339
Which muscles does the cervical branch of the facial nerve innervate?
platysma
340
Describe the course of the chorda tympani
arises in the facial canal
travels across the bones of the middle ear, exiting via the petrotympanic fissure
enters the infratemporal fossa
‘hitchhikes’ with the lingual nerve
341
Describe the corneal reflex
stimulus = tactile, thermal or painful stimulation of the cornea
afferent limb = ophthalmic nerve of the trigeminal nerve detecting the stimuli.
efferent limb = the facial nerve is the , causing bilateral contraction of the orbicularis oculi muscle
342
Where will a pupil sparing lesion of the occulomotor nerve be?
distal to the ciliary ganglion
| so will not affect the sphincter pupillae
343
What are the symptoms and signs of an intracranial facial nerve palsy?
Why?
reduced salivation and loss of taste on the ipsilateral 2/3 of the tongue - Chorda tympani
ipsilateral hyperacusis (hypersensitive to sound) - nerve to stapedius
ipsilateral reduced lacrimal fluid production - Greater petrosal nerve
344
Which cranial nerves carry parasympathetic fibres?
CN III
CN VII
CN IX
CN X
345
Which structures are innervated by the parasympathetic fibres carried by CN III?
sphincter pupillae
| ciliary muscles of the eye
346
Which structures are innervated by the parasympathetic fibres carried by CN VII?
mucous glands of the oral cavity, nose and pharynx
lacrimal gland
submandibular and sublingual salivary glands
347
Which structures are innervated by the parasympathetic fibres carried by CN IX?
parotid gland.
348
Which structures are innervated by the parasympathetic fibres carried by CN X?
heart
| GI system
349
Where do the sympathetic fibres supplying the head and neck originate from?
T1-T6
350
What is the sympathetic chain?
spans from the base of the skull to the coccyx
| formed of nerve fibres and ganglia
351
What structures do sympathetic fibres travel along to reach somatic targets?
segmental nerves
352
What structures do sympathetic fibres travel along to reach visceral targets?
ganglionated trunks
353
Describe the anatomical location of the superior cervical ganglion
posteriorly to the carotid artery
| anterior to the C1-4 vertebrae.
354
Which arteries do the nerves from the superior cervical ganglion hitch hike along?
common carotid
external carotid
internal carotid
355
Which structures does the superior cervical ganglion innervate?
```
eyeball
face
nasal glands
pharynx
salivary glands
lacrimal gland
sweat glands
dilator pupillae
superior tarsal muscle
carotid body
heart
arterial smooth muscles
```
356
Describe the anatomical location of the middle cervical ganglion
anteriorly to the inferior thyroid artery and the C6 vertebra
absent in some individuals
357
Which arteries do the nerves from the middle cervical ganglion hitch hike along?
inferior thyroid
358
Which structures does the middle cervical ganglion innervate?
```
larynx
trachea
pharynx
upper oesophagus
heart
arterial smooth muscle
```
359
Describe the anatomical location of the inferior cervical ganglion
anteriorly to the C7 vertebra
360
Which arteries do the nerves from the inferior cervical ganglion hitch hike along?
vertebral
| subclavian
361
What causes Horner's syndrome?
```
sympathetic fibres stretched or damaged in the head and neck
Due to...
spinal cord lesions
traumatic injury
pancoast tumour (affecting apex of lung)
```
362
What are the signs and symptoms of Horner's syndrome?
Why?
* Partial Ptosis– drooping of the upper eyelid. This is due to paralysis of the superior tarsal muscle, which acts to help open the eyelid.
* Miosis – constriction of the pupil. This is due to paralysis of the dilator pupillae, a muscle located within the eye that acts to dilate the pupil.
* Anhydrosis – decreased sweating (affecting the same side of the face as the lesion). This is due to a loss of innervation to the sweat glands of the face.
363
What effects does an increase in sympathetic stimulation have to the head and neck?
pupillary dilation
vaso-constriction
lid retraction
sweating
364
Name the four parasympathetic ganglia in the head
ciliary,
otic,
pterygopalatine
submandibular
365
Where do the parasympathetic fibres of the head originate?
four nuclei in the brainstem
366
Where is the ciliary ganglion located?
within the bony orbit
anterior to superior orbital fissure
between lateral rectus and optic nerve
367
Where do the pre-ganglionic fibres entering the ciliary ganglion originate?
Edinger-Westphal nucleus
368
Which nerve are the pre-ganglionic fibres of the ciliary ganglion associated with?
occulomotor nerve - inferior division
369
Name the post-ganglionic fibres of the ciliary ganglion
short ciliary nerves
370
What are the target organs of the post-ganglionic parasympathetic fibres of the ciliary ganglion?
What is their effect?
sphincter pupillae - constricts the pupil
| ciliary muscles - contracts to make lens more spherical, accommodating near vision
371
What is Adie's pupil?
| What is the cause?
dilated pupil that does not constrict in the presence of light
ciliary ganglion is damaged, due to infection and subsequent inflammation, so there is a loss of innervation to the sphincter pupillae
372
Where is the pterygopalatine ganglion located?
within the pterygopalatine fossa
inferior to the base of the skull
posterior to the maxilla.
373
Where do the pre-ganglionic fibres entering the pterygopalatine ganglion originate?
superior salivary nucleus
374
Which nerve are the pre-ganglionic fibres of the pterygopalatine ganglion associated with?
facial nerve - greater petrosal nerve
375
Which nerve are the post-ganglionic fibres of the pterygopalatine ganglion associated with?
maxillary nerve V2
376
What are the target organs of the post-ganglionic parasympathetic fibres of the pterygopalatine ganglion?
What is their effect?
lacrimal gland
mucous glands of posterosuperior nasal cavity, nasopharynx, and the palate
secretion
377
Where do the pre-ganglionic fibres entering the submandibular ganglion originate?
the superior salivary nucleus
378
Which nerve are the pre-ganglionic fibres of the submandibular ganglion associated with?
carried within CN VII - chorda tympani
| hitchhikes along lingual branch of the mandinbular nerve CNV
379
Describe the post-ganglionic fibres of the submandibular ganglion
Fibres leave the ganglion and travel directly to the submandibular and sublingual glands.
380
What are the target organs of the post-ganglionic parasympathetic fibres of the submandibular ganglion?
What is their effect?
submandibular and sublingual salivary glands
secretion
381
Where is the otic ganglion located?
inferiorly to the foramen ovale within the infratemporal fossa
medial to the mandibular branch of the trigeminal nerve.
382
Where do the pre-ganglionic fibres entering the otic ganglion originate?
inferior salivary nucleus
383
Which nerve are the pre-ganglionic fibres of the otic ganglion associated with?
CN IX - lesser petrosal nerve
384
Which nerve are the post-ganglionic fibres of the otic ganglion associated with
auricotemporal nerve - branch of CN V3
385
What are the target organs of the post-ganglionic parasympathetic fibres of the otic ganglion?
What is their effect?
parotid gland
secretion
386
Where do the parasympathetic fibres associated with the vagus nerve originate?
dorsal vagus motor nucleus
387
What are the target organs of the post-ganglionic parasympathetic fibres associated with the vagus nerve?
What is their effect?
smooth muscle of the trachea, bronchi and GI tract
| glands in laryngopharynx, oesophagus and trachea
388
State the boundaries of the oral cavity
anterior - oral fissure
| posterior - oropharyngeal isthmus
389
Name the two divisions of the oral cavity
vestibule
| mouth cavity proper
390
State the boundaries of the vestibule
anterior - oral fissure
| posterior - upper and lower dental arches
391
Where is the opening of the parotid duct?
Opposite the upper second molar tooth
| salivary juices are secreted into the vestibule
392
State the boundaries of the mouth proper
anterior - upper and lower dental arches
| posterior - oropharyngeal isthmus
393
What forms the hard palate?
maxilla
| palatine bone
394
What forms the soft palate?
```
muscles!
palatoglossus
palatopharyngeus
tensor veli palatini
levator veli palatini
```
395
What are the actions of the soft palate?
lowers to close the oropharyngeal isthmus,
| elevates to separate the nasopharynx from the oropharynx
396
DEscribe the innervation of the muscles of the soft palate
vagus nerve
apart from tensor veli palatini = CN V3
397
What forms the palatoglossal arch?
palatoglossus muscle
398
What forms the palatopharyngeal arch?
palatopharyngeus
399
Where do the submandibular glands enter the oral cavity?
papillae either side of lingual frenulum
400
Describe the sensory innervation of the oral cavity
trigeminal nerve
palate - greater palatine and nasopalatine CN V2
floor - lingual CN V3
cheeks - buccal CN V3
401
Describe the special sensory innervation of the tongue
anterior 2/3rds - chorda tympani CN VII
posterior 1/3rd - glossopharyngeal
402
Describe the clinical appearance of the uvula losing its innervation
unilateral vagus nerve denervation
| uvula points AWAY from lesion
403
What are the gingivae composed of?
dense fibrous connective tissue
| covered by smooth and vascular mucous membrane
404
Describe the innervation of the intrinsic muscles of the tongue
hypoglossal nerve
405
State the name and action of the intrinsic muscles of the tongue
* superior longitudinal – sides of tongue up
* vertical – flatten and broadens
* transverse – pulls sides of tongue in to push tongue out
* inferior longitudinal - sides of tongue down
406
Describe the sensory innervation of the tongue
anteriorly - lingual nerve CN Vs
| posteriorly - glossopharyngeal nerve CN IX
407
What causes Dental Caries?
trauma or inadequacy of the enamel causes the hard layer of enamel to be broken down
the most common cause of breakdown of enamel is by lactic acid that is formed by bacteria when sugars are left in contact with the teeth.
408
What are the risk factors for dental caries?
a diet high in sugars
| poor dental hygiene
409
Describe the presenting features of a patient with tonsillitis
```
pain in throat
pain on swallowing
headache
hoarse voice
fever
swollen jugolodigastric lymph nodes
erythema of tonsils
pus on tonsils
swollen tonsils
```
410
State the common causes of tonsillitis
rhinovirus
influenza
group A streptococci
411
Describe the treatment of tonsillitis
pain relief
severe bacterial cases:
penicillin
412
Where is pus trapped in a peritonsillar abscess?
trapped between the palatine tonsillar capsule and the lateral pharyngeal wall
413
Describe the presenting features of a patient with a peritonsillar abscess
```
severe sore throat
hoarse/croaky voice
dysphagia
fever.
Stridor
uvula deviates away from abscess
```
414
Why is anaphylaxis of great danger in the oral cavity?
space between the oral cavity and the oropharynx can become obstructed due to the severe swelling of the tissues
AIRWAY OBSTRUCTION
415
Anterior to posterior, name the teeth
```
central incisor
lateral incisor
canine
first premolar
second premolar
first molar
second molar
third molar
```
416
State the location of the Adenoid tonsils
at the bottom of the nasopharynx
417
State the location of the tubal tonsils
end of the Eustachian tube
418
State the location of the palatine tonsils
between the anterior and posterior arches
419
State the location of the lingual tonsils
at the back of the tongue
420
Where are the mastoid air cells found?
in the mastoid antrum of the mastoid process of the temporal bone
421
What is the function of the mastoid air cells?
act as a reservoir of air
| releases air into the tympanic cavity when pressure is too low
422
Which portion of the temporal bone contains the inner ear?
petrous part
423
Which portion of the temporal bone contains the outer ear?
tympanic
424
How is mastoiditis caused?
Middle ear infections (otitis media) can spread to the mastoid air cells
425
Why does mastoiditis lead to meningitis?
sigmoid venous sinus lies behind the air cells
| spread of infection leads to meningitis
426
Name the parts of the ear
lobule - only part not supported by cartilage.
```
helix = The outer curvature of the ear
antihelix = curved elevation, which is parallel to the helix but inner
```
The antihelix divides into two cura superiorly – the inferoanterior crus, and the superoposterior crus.
concha = hollow depression in the middle of the auricle
It continues into the skull as the external acoustic meatus.
tragus = Immediately anterior to the start of the external acoustic meatus
antitragus = Opposite the tragus
427
Describe the blood supply to the outer ear
posterior auricular, superficial temporal and occipital arteries and veins.
428
What is an auricular haematoma?
blood collects between the cartilage and the overlying perichondrium
429
Describe a complication of an auricular haematoma
accumulation of blood disrupts the vascular supply to the cartilage of the pinna.
If it is not drained quickly, a gross deformity results, called ‘cauliflower ear‘.
430
Describe the sensory innervation of the external acoustic meatus
mandibular CN V3
| vagus nerves.
431
What is ear wax made up of?
cerumen (modified sebum)
| dead skin cells
432
Describe the course of the external acoustic meatus
* Initially travels in a superoanterior direction.
* Turns slightly to move superoposterior.
* Ends in an inferoanterior direction.
433
Describe the structure of the tympanic membrane
double layered structure
skin on the outside
mucous membrane on the inside
434
Name the point that the handle of the malleus attaches to the tympanic membrane
umbo
435
What causes perforation of the tympanic membrane?
trauma
| infection
436
How does otitis media lead to tympanic membrane perforation?
pus and fluid to build up.
increase in pressure
the eardrum ruptures
437
State the boundaries of the middle ear
* Roof – Formed by a thin bone from the petrous part of the temporal bone. It separates the middle ear from the middle cranial fossa.
* Floor – Known as the jugular wall, it consists of a thin layer of bone, which separates the middle ear from the internal jugular vein
* Lateral Wall – This is made up of the tympanic membrane and the lateral wall of the epitympanic recess.
* Medial Wall – Formed by the lateral wall of the internal ear. It contains a prominent bulge, produced by the facial nerve as it travels nearby.
* Anterior Wall – The anterior wall is a thin bony plate with two openings; for the auditory tube and the tensor tympani muscle. It separates the middle ear from the internal carotid artery.
* Posterior Wall – Also known as the mastoid wall, it consists of a bony partition between the tympanic cavity and the mastoid air cells. Superiorly, there is a hole in this partition, allowing the two areas to communication. This hole is known as the aditus to the mastoid antrum.
438
Name the bones of the middle ear
malleus
incus
stapes
439
How are the tympanic membrane and the inner ear connected?
auditory ossicles link up to connect it to the oval window
440
How is the middle ear divided?
tympanic cavity = medially to the tympanic membrane. It contains the majority of the bones of the middle ear.
epitympanic recess = superiorly, near the mastoid air cells.
441
How do the mastoid air cells communicate with the middle ear?
aditus to the mastoid antrum
442
Which muscles have a protective function in the middle ear?
tensor tympani
| stapedius.
443
Describe the action of the tensor tympani and stapedius
acoustic reflex = contract in response to loud noise
inhibit the vibrations of the malleus, incus and stapes,
reducing the transmission of sound to the inner ear
444
Describe the innervation of the tensor tympani and the stapedius
tensor tympani = mandibular nerve
stapedius = facial nerve
445
Describe the course of the Eustachian tube
extends from the anterior wall of the middle ear
in an anterior, medioinferior direction,
opening onto the lateral wall of the nasopharynx at the inferior nasal concha
446
What causes otitis media?
dysfunction of the auditory tube
| negative pressure inside middle ear
447
How is otitis media observed?
tympanic retraction
448
What causes otitis media with effusion?
the negative pressure inside the middle ear leads to a transudate being secreted from the mucosa
chronic accumulation of fluid
449
What is the function of the ossicles?
amplify and concentrate sound energy from the eardrum to the oval window
450
What are the functions of the inner ear?
* To convert mechanical signals from the middle ear into electrical signals, which can transfer information to the auditory pathway in the brain.
* To maintain balance by detecting position and motion.
451
Where is the oval window of the inner ear found?
between the middle ear and the vestibule
452
Where is the round window of the inner ear found?
between the middle ear and the scala tympani (part of the cochlear duct).
453
Name the parts of the bony labyrinth
semi-circular canals
vestibule
cochlea
454
What is inside the bony labyrinth?
lined by periosteum
| contain perilymph
455
Describe the anatomical location of the vestibule
within the petrous part of the temporal bone
posterior to cochlea
anterior to semicircular canals
456
What is located within the vestibule?
saccule
| utricle
457
What is the modiolus?
the central portion of bone in the cochlea
| spiral lamina extend from it
458
Where is the scala vestibuli found?
superiorly to the cochlear duct.
| it is continuous with the vestibule
459
Where is the scala tympani found?
inferiorly to the cochlear duct.
| terminates at the round window.
460
Where is the membranous labyrinth found?
within the bony labyrinth, surrounded by perilymph
461
Name the parts of the membranous labyrinth
cochlear duct,
semicircular ducts,
utricle
saccule
462
What is the membranous labyrinth filled with?
endolymph
463
What is Reissner's membrane?
membrane that separates the cochlear duct from the scala vestibuli
464
What is the basilar membrane?
membrane that separates the cochlear duct from the scala tympani
contains the epithelial cells of hearing - Organ of Corti
465
What is the function of the saccule?
receives fluid from the cochlear duct
466
What is the function of the utricle?
receives fluid from the semicirular ducts
467
Where are the sensory receptors that detect movement and allow process of balance?
ampullae of the semicircular canals
468
What causes Meniere's disease?
disorder of the inner ear
excess accumulation of endolymph within membranous labyrinth
distension of the ducts
pressure fluctuations damage the membranes
469
What are the symptoms of Meniere's disease?
vertigo
tinnitus
hearing loss
470
Describe the innervation of the inner ear
vestibulocochlear nerve
* Vestibular nerve – enlarges to form the vestibular ganglion, which then splits into superior and inferior parts to supply the utricle, saccule and three semicircular duct.
* Cochlear nerve – enters at the base of the modiolus and its branches pass through the lamina to supply the receptors of the Organ of Corti.
471
Why is the facial nerve vulnerable to damage from middle ear disease?
lies in facial canal
| separated from middle ear by thin bony partition
472
Describe the sensory innervation of the auricle
superior - auricotemporal
inferior and posterior - greater auricular CN V2
473
Why do patients complain of an involuntary cough when cleaning their ears?
stimulation of the auricular branch of the vagus nerve
cough reflex
474
Describe the innervation of the tympanic membrane
Outer tympanic membrane = auricotemporal CN V3 and vagus
Inner tympanic membrane = glossopharyngeal
475
What causes Benign Paroxysmal Positional Vertigo?
otoliths detach from lining of vestibule and enter the semicircular ducts
Detached otoliths may continue to move after the head has stopped moving
movement detected by vestibular nerve
vertigo results from the conflicting sensation of ongoing movement with other sensory inputs.
476
How is the external acoustic meatus examined?
pull auricle upwards and backwards
NB: downwards and backwards in children!
477
Describe conductive hearing loss
o Results from anything in the external or middle ear that interferes with the conduction of sound or movement of the oval or round windows.
o People with this type of hearing loss often speak with a soft voice
To them, their own voices sound louder than background sounds
478
`Describe sensorineural hearing loss
o Results from defects in the pathway from cochlea to brain
Defects of cochlea
Defects of cochlea nerve
Defects of brainstem
o Cochlear implants can restore hearing
External microphone transmitting to an implanted receiver that sends electrical impulses to the cochlea, stimulating the cochlear nerve
479
describe the Rinne and Weber's tests
Rinne = tuning fork held in front of ear and then on mastoid process
Webers = tuning fork held in middle of forehead
480
What does Rinne's examine?
conductive hearing loss
| if bone > air
481
What does Weber's examine?
Localisation of sound
482
How will conductive hearing loss present on Rinne and Weber's?
```
Rinne = bone > air
Weber's = localise to affected ear
```
483
What shape is the bony orbit?
pyramid
484
State the boundaries of the bony orbit
* Roof – frontal bone and the lesser wing of the sphenoid.
* Floor – maxilla, palatine and zygomatic bones.
* Medial wall – ethmoid, maxilla, lacrimal and sphenoid bones.
* Lateral wall – zygomatic bone and greater wing of the sphenoid.
* Apex – the optic foramen.
* Base – Opens out into the face, and is bounded by the eyelids. It is also known as the orbital rim.
485
How is the orbit separated from the anterior cranial fossa?
The frontal bone
486
How is the orbit separated from the maxillary sinus?
The maxilla
487
How is the orbit separated from the ethmoid sinus?
The ethmoid bone
488
What structures does the bony orbit contain?
• Extra-ocular muscles
• Nerves: optic, oculomotor, trochlear, trigeminal and abducens nerves.
• Blood vessels: ophthalmic artery, central retinal artery,central retinal vein, inferior and superior ophthalmic veins
Orbit fat
489
When the eye is medial, which muscles act to move it up and down?
obliques
490
When the eye is lateral, which muscles act to move it up and down?
rectus
491
Where do the rectus muscles originate from?
common tendinous ring
492
Describe the action of the superior rectus
elevation.
| Also contributes to adduction and medial rotation of the eyeball.
493
Describe the action of the inferior rectus
depression.
| Also contributes to adduction and lateral rotation of the eyeball.
494
Describe the action of the medial rectus
Adducts the eyeball.
495
Describe the action of the lateral rectus
Abducts the eyeball.
496
Where does the superior oblique originate from and attach to?
sphenoid bone
| posterior to the superior rectus
497
Describe the action of the superior oblique
Depresses, abducts and medially rotates the eyeball
498
Describe the action of the inferior oblique
Elevates, abducts and laterally rotates the eyeball.
499
State the innervation of the extraocular muscles
CN III: others
CN IV: superior oblique
CN VI: lateral rectus
500
What passes through the optic canal?
optic nerve
| ophthalmic artery
501
What passes through the superior orbital fissure?
```
lacrimal nerve
frontal nerve
CN IV
CN III
nasociliary nerve
CN VI
superior ophthalmic vein
```
502
What passes through the inferior orbital fissure?
maxillary nerve (a branch of CN V),
inferior ophthalmic vein
sympathetic nerves.
503
Where is the nasolacrimal canal located?
medial wall of the orbit
504
Where is the lacrimal gland located?
in a fossa on the superolateral part of the orbit
505
What is the function of the lacrimal canaliculi?
Commence at the medial angle of the eye where lacrimal fluid is drained into the lacrimal sac
506
What is the function of the nasolacriml duct?
Conveys lacrimal fluid to the inferior nasal meatus
507
What is the function of the sclera and cornea?
provide shape to the eye
support the deeper structures
sclera provides attachment to the extraocular muscles
cornea refracts light entering the eye
508
What is the choroid?
layer of connective tissue and blood vessels, providing nourishment to the outer layers of the retina
509
What makes up the ciliary body?
ciliary muscle
| ciliary processes
510
What is the function of the ciliary body?
ciliary smooth muscles attached to the lens by the ciliary processes
controls the shape of the lens
also contributes to formation of aqueous humour
511
Describe the layers of the retina
* Neural layer – Consists of photoreceptors, located posteriorly and laterally in the eye.
* Pigmented layer – Lies underneath the neural layer and is attached to the choroid layer. It acts to support the neural layer, and continues around the whole inner surface of the eye.
512
Where is the non-visual retina found?
anteriorly (no neural layer)
513
Where is the optic retina found?
Posteriorly and laterally, both layers of the retina are present
514
How can the optic part of the retina be viewed?
ophthalmoscopy
515
Where is the macula found?
| How can it be identified?
centre of the retina
| highly pigmented - yellow
516
Where is the fovea found?
depression in the centre of the macula
517
What is the fovea responsible for?
high acuity vision
518
Where does the optic nerve enter the retina?
optic disc
519
Describe the location of the lens
between the vitreous humor and the pupil
520
Explain the difference between the anterior and posterior segments of the eye
The anterior segment of the eye contains aqueous humor and supplies the lens of the eye. In front of lens.
The posterior segment of the eye contains vitreous humor and keeps the eye in shape. Behind lens
521
Explain the difference between the anterior and posterior chambers of the eye
The anterior chamber is located between the cornea and the iris.
The posterior chamber is located between the iris and ciliary processes.
Both located in the anterior segment and filled with aqueous humour
522
Describe the arterial supply of the eyeball
the ophthalmic artery - a branch of the internal carotid artery
523
Describe the arterial supply of the internal surface of the retina
central artery of the retina
a branch of the ophthalmic artery
branch of the internal carotid artery
524
Describe the venous drainage of the eyeball
the superior and inferior ophthalmic veins.
| These drain into the cavernous sinus
525
What is an orbital rim fracture?
fracture of the bones forming the outer rim of the bony orbit.
It usually occurs at the sutures joining the three bones of the orbital rim – the maxilla, zygomatic and frontal.
526
What is a blowout fracture?
partial herniation of the orbital contents through one of its walls.
The medial and inferior walls are the weakest, with the contents herniating into the ethmoid and maxillary sinuses respectively
527
What is the cause of a blowout fracture?
blunt force trauma to the eye
528
What are the clinical consequences of a fracture to the bony orbit?
```
increased intraorbital pressure
raising the pressure in the orbit,
causing exophthalmos (protrusion of the eye)
```
529
What lines the inner surface o the eyelids?
conjuctiva
530
Which muscles acts to elevate the eyelid?
levator palpebrae superioris
531
How is the superior tarsal muscle innervated?
sympathetic nervous system
532
How is the levator palpebrae superioris innervated?
oculomotor nerve (CN III)
533
What structure does a Meibomian Cyst affect?
tarsal gland, lying behind the eyelash
534
What structure does a Stye affect?
ciliary gland
535
What is a key difference between a Meibomian Cyst and a Stye?
stye = infective. most commonly Staph A
536
Explain the difference between partial and complete ptosis with regards to the neural innervation of the eyelid
Partial ptosis = loss of sympathetic innervation of superior tarsal
Complete ptosis = oculomotor lesion, damage to levator palpabrae superioris
537
What is glaucoma?
an increase in intra-ocular pressure, secondary to an increased amount of aqueous humor
538
what are the consequences of glaucoma?
compression of the retinal arteries,
damage to the retina
loss of vision
539
Describe closed angle glaucoma
iris is forced against the trabecular meshwork, preventing any drainage of aqueous humor
OPTHALMIC EMERGENCY
540
Describe open angle glaucoma
the outflow of aqueous humor through the trabecular meshwork is reduced.
It causes a gradual reduction of the peripheral vision, until the end stages of the disease.
541
What causes cataracts?
disruption of the crystallin fibres within the lens, leading to protein aggregation in lens
accumulation of pigment within the lens
causing, light scattering, obstruction of vision
542
What are the symptoms of cataracts?
gradual painless loss of vision,
diplopia in one eye
haloes
543
What are the symptoms of conjunctivitis?
* Red eye - usually generalised, often bilateral.
* Irritation, grittiness and discomfort
* Discharge - may be watery, mucoid, sticky or purulent depending on the cause.
* Photophobia - this suggests corneal involvement.
* Visual acuity unaltered -
544
What is orbital cellulitis?
infection of the soft tissues behind the orbital septum (separates the eyelids from the contents of the orbital cavity)
545
What are the symptoms of orbital cellulitis?
sudden onset of unilateral swelling of conjunctiva and eyelids, pain and sticky discharge.
Fever,
painful eye movements
decreased vision
proptosis (eye pushed forwards)
RAPD (Relative Afferent Pupillary Defect)
546
Describe the signs and symptoms of an occulomotor nerve lesion
affected eye is displaced laterally by the lateral rectus and inferiorly by the superior oblique.
The eye adopts a position known as ‘down and out’. There will also be a dilated pupil (loss of sympathetic dilator pupillae) and ptosis.
547
Describe the signs and symptoms of a trochlear nerve lesion
paralysis of superior oblique
problem rotating the eye
diplopia (double vision)
head tilt away from the site of the lesion
548
Describe the signs and symptoms of an abducens nerve lesion
paralysis of lateral rectus
| affected eye will adducted by the resting tone of the medial rectus.
549
What is papilloedema?
optic disc swelling secondary to raised intracranial pressure (ICP)
550
What are the symptoms of raised intracranial pressure?
headache (worse on waking, straining and bending)
nausea
vomiting
551
How can the central retinal artery become occluded?
embolus
552
What are the symptoms of central retinal artery occlusion?
sudden (over a few seconds), unilateral painless visual loss
553
What will be seen on examination of central retinal artery occlusion?
afferent pupillary defect
pale retina with attenuation of the vessels.
centre of the macula (supplied by the intact underlying choroid) stands out as a cherry-red spot.
554
How can the central retinal vein become occluded?
thrombophlebitis
| thrombus formation
555
What are the symptoms of central retinal vein occlusion?
sudden painless unilateral loss of vision
556
Describe the pathophysiology of central retinal vein occlusion
backlog of stagnated blood combined with hypoxia
results in extravasation of blood constituents, causing further stagnation
Ischaemic damage to the retina stimulates increased production of vascular endothelial growth factor (VEGF)
neovascularisation - can result in haemorrhage or neovascular glaucoma (the new vessels grow into the aqueous drainage system, so clogging it up)
557
What will be seen on examination of non-ischaemic central retinal vein occlusion?
mild or absent afferent pupillary defect.
widespread dot-blot and flame haemorrhages throughout the fundus
some disc oedema
558
What will be seen on examination of ischaemic central retinal vein occlusion?
marked afferent pupillary defect.
widespread dot-blot and flame haemorrhages throughout the fundus
disc oedema is more severe. Haemorrhages scattered throughout the fundus in typical blood-storm pattern with cotton wool spots
occasionally be an associated retinal detachment.
559
What are the symptoms of retinal detachment?
flashes of light
| specks floating in the eye
560
What are the afferent fibres of the corneal reflex?
Opthalmic Branch of the Trigeminal Nerve (CN V1)
561
What are the efferent fibres of the corneal reflex?
Temporal and Zygomatic Branches of the Facial Nerve (CN VII)
562
What is the response of the corneal reflex?
Contraction of the Orbicularis Oculi, causing the eye to blink
563
What is an RAPD?
one eye doesn't sense light as well as the other
swinging light test
eye dilates instead of constricts
564
What are the afferent fibres of the light reflex?
Optic nerve (carries impulse to brain)
565
What are the efferent fibres of the light reflex?
Parasympathetic fibres travel along CN III via the edinger westphal nucleus and ciliary ganglion to cause constriction of iris and ciliary muscle of lens
566
What is used to asses visual acuity?
Snellen Chart
567
Describe the features of the external nose
nasal root = superiorly, continuous with the forehead. apex = inferior rounded ‘tip’. dorsum = between the root and apex
nares = immediately inferiorly to the apex, piriform openings into the vestibule of the nasal cavity
nasal septum = medial boundary of nares
ala nasi = lateral cartilaginous wings nares
568
What is the skeleton of the nose composed of?
cartilage inferiorly
| bone superiorly
569
State the bony components of the nasal skeleton
nasal bones,
maxillae
frontal bone.
570
State the cartilaginous components of the nasal skeleton
the two lateral cartilages,
two alar cartilages
one septal cartilage.
There are also some smaller alar cartilages present
571
Identify the structures that make up the septum of the nasal cavity
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o Anterior Portion
Septal cartilage
o Middle Portion
Perpendicular plate of the Ethmoid Bone
o Posterior Portion
Vomer
o Inferiorly,
the hard palate, made up of the palatine posteriorly and maxillary bones anteriorly
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572
What forms the inferior concha?
independent bone - inferior concha!
573
What forms the superior and middle concha?
medial processes of the ethmoid bone
574
Where is the sphenoethmoidal recess?
superior and posterior to the superior concha
575
What is the function of the conchae?
increase the surface area of the nasal cavity – this increases the amount of heat exchange.
disruption of the fast, laminar flow of air, making it slow and turbulent.
The air spends longer in the nasal cavity, so that it can be humidified.
576
What communicates with the nasal cavity via the cribriform plate?
olfactory nerve
| CSF
577
What communicates with the nasal cavity via the sphenopalatine foramen?
pterygopalatine fossa
sphenopalatine artery
nasopalatine nerve
superior nasal nerve
578
Where is the sphenopalatine foramen located?
superior meatus
| posterior
579
What communicates with the nasal cavity via the incisive foramen?
incisive fossa of oral cavity
nasopalatine nerve
greater palatine artery
580
What are the functions of the nasal cavity?
* Warms and humidifies the inspired air.
* Removes and traps pathogens and particulate matter from the inspired air.
* Responsible for sense of smell.
* Drains and clears the paranasal sinuses and lacrimal ducts.
581
What are the regions of the nasal cavity?
vestibule
olfactory region
respiratory region
582
Where is the vestibule of the nasal cavity?
the area surrounding the external opening to the nasal cavity.
583
Describe the olfactory region of the nasal cavity
at the apex of the nasal cavity.
| It is lined by olfactory cells with olfactory receptors.
584
Describe the respiratory region of the nasal cavity
lined by ciliated psudeostratified epithelium. Within the epithelium are interspersed mucus-secreting goblet cells.
585
When do the frontal sinuses appear?
7
586
Where do the frontal sinuses drain into the nasal cavity?
via the frontonasal duct
to the ethmoidal infundiubulum
middle meatus - hiatus semilunaris
587
Describe the relation of the sphenoid sinus to the pituitary gland and how it can be utilised in surgery
the pituitary gland can be surgically accessed via passing through the nasal roof, into the sphenoid sinus and through the sphenoid bone
588
Where do the sphenoid sinuses drain into the nasal cavity?
Sphenoethmoidal Recess
589
Where do the anterior ethmoid sinuses drain into the nasal cavity?
middle meatus via the infundibulum
590
Where do the middle ethmoid sinuses drain into the nasal cavity?
directly into the middle meatus
591
Where do the posterior ethmoid sinuses drain into the nasal cavity?
superior meatus
592
Describe the anatomical relations of the maxillary sinus
roof = floor of the orbit,
floor = the alveolar part of the maxilla (relating them to the roots of the first two molars and the superior alveolar nerve.)
Posteriorly lie the pterygopalatine and infratemporal fossae.
593
Where do the maxillary sinuses drain into the nasal cavity?
at the hiatus semilunaris, underneath the frontal sinus opening in the middle meatus.
594
Describe the anatomical relations of the ethmoid sinus
lateral to the orbit of the eye
595
Which structures drain into the middle meatus?
The frontal, maxillary and anterior ethmoidal sinuses
= semilunar hiatus anteriorly
Middle ethmoidal sinus = ethmoid bulla posteriorly
596
Which structures drain into the superior meatus?
posterior ethmoidal sinuses
597
Which structures drain into the inferior meatus?
nasolacrimal duct anteriorly
| Eustachian tube posteriorly
598
Describe the arterial supply to the nose
Internal carotid branches:
• Anterior ethmoidal artery
• Posterior ethmoidal artery
- branches of the opthalmic artery.
External carotid branches:
• Sphenopalatine artery
• Greater palatine artery
• Superior labial artery
599
What is Kiesselbach's area?
anastomoses in anterior third of nasal septum
600
Where do the veins of the nose drain into?
pterygoid plexus,
facial vein
cavernous sinus
601
Describe the general sensory innervation of the nose
posteroinferior septum and lateral walls = nasociliary nerve (branch of the ophthalmic nerve CN V2)
anterosuperior septum and lateral walls = nasopalatine nerve (branch of maxillary nerve CN V1)
external skin = trigeminal nerve (V1/V2)
602
How can epistaxis be managed clinically?
first achieved by pinching of the bridge of the nose whilst sitting with the head forwards.
This prevents aspiration or swallowing of blood.
Cautery can be useful if bleeding does not stop.
Nasal tampons, posterior packing and surgical ligation of nasal arteries can be used in very severe bleeds.
603
What causes saddle nose deformity?
direct damage to the septal bone or cartilage, or a consequence of nasal septal haematoma
septal support to the nose is lost,
the middle part of the nose appears sunken
604
Describe the clinical presentation of a severe nasal septal deviation
obstructs breathing
| snoring.
605
What is rhinitis?
Inflammation of the nasal mucosa, leading to swelling and increased volume of secretion
606
What causes rhinitis?
```
o Infective (Viral)
Adenovirus
Rhinovirus
Respiratory Syncytial Virus (RSV)
o Allergic
o Nasal Polyps
```
607
What are nasal polyps?
lesions arising from the nasal mucosa, occurring at any site in the nasal cavity or paranasal sinuses
608
Where are nasal polyps most commonly seen?
the clefts of the middle meatus
609
How can a nasal infection spread to the anterior cranial fossa?
cribriform plate
610
How can a nasal infection spread to the lacrimal apparatus and conjunctiva?
nasolacrimal duct
611
How can a nasal infection spread to the middle ear?
Eustachian tube
612
What causes sinusitis?
Viral infection with a secondary bacterial infection with Streptococcus pneumoniae or Haemophilus influenzae
613
Why can sinusitis present as tooth ache?
The maxillary nerve supplies both the maxillary sinus and maxillary teeth
