ENT Embryology + Anatomy Flashcards
1
Q
When do the pharyngeal arches develop?
A
Weeks 4 & 5 gestation
2
Q
On what day does Arch 1 begin to develop?
A
Day 22
3
Q
On which day do arches 2 & 3 begin to develop?
A
Day 24
4
Q
On which day do arches 4 and 6 begins to develop?
A
Day 29
5
Q
What separates the arches externally?
A
Pharyngeal clefts
6
Q
What separates the arches internally?
A
Pharyngeal pouches
7
Q
What lines the pharyngeal clefts?
A
Ectoderm
8
Q
What lines the pharyngeal pouches?
A
Endoderm
9
Q
What does the mesenchyme of the arches form?
A
Musculature of the face
10
Q
What does the neural crest of the arches form?
A
Skeletal components of the face
11
Q
What does the artery in the arches form?
A
Aortic arches
12
Q
Which CNs cover arch 1?
A
CNV2, V3
13
Q
Which CNs cover arch 2?
A
CNVII
14
Q
Which CNs cover arch 3?
A
CNIX
15
Q
Which CNs cover arch 4?
A
Superior laryngeal branch of CNX
16
Q
Which CNs cover arch 6?
A
Recurrent laryngeal branch of CN X
17
Q
What does Meckel’s cartilage give rise to?
A
Inchus, malleus and mandible
18
Q
Where does Meckel’s cartilage develop from?
A
Ventral portion/mandibular process of the first arch
19
Q
What does the dorsal portion of the first arch give rise to?
A
Zygoma; maxilla and part of the temporal bone.
20
Q
Which muscles does arch 1 give rise to?
A
Muscles of mastication; anterior belly of digastric muscle, mylohyoid, tensor tympani and tensor palatine.
21
Q
Which muscles does arch 2 give rise to?
A
Muscles of facial expression, stapedius, stylohyoid, posterior belly of digastric and auricular.
22
Q
What muscle does arch 3 give rise to?
A
Stylopharyngeus
23
Q
What do arches 4 and 6 give rise to?
A
Laryngeal cartilages
24
Q
What does the 1st pharyngeal cleft form?
A
External auditory meatus
25
What do the 2nd - 4th pharyngeal clefts form?
Cervical sinus
26
What does the 1st pharyngeal pouch form?
Middle ear, Eustachian tube and tympanic membrane
27
What does the 2nd pharyngeal pouch form?
Palatine tonsil
28
What does the 3rd pharyngeal pouch give rise to?
Inferior parathyroid gland and thymus
29
What does the 4th pharyngeal pouch give rise to?
Superior parathyroid gland and the C cells of the thyroid gland
30
What does the inner ear develop from?
Otic placodes
31
What do the semi-circular canals develop from?
Utricular part of the otic vesicle
32
What is the modiolus?
A spongy bone structure which acts as the axis of the cochlea
33
What is the bony nasal septum made of?
Ethmoid bone superiorly, vomer inferiorly
34
What is the function of ostia?
Drain mucous into the nasal cavity
35
Where are the ostia?
On the lateral walls of the nasal septum
36
Describe the mucosa of the nasal cavity.
Immediately past the nostril -kertatinised stratified squamous epithelium
Main body - respiratory epithelium
Superior and deep top corner - olfactory
37
Which nerve passes through the cribiform plate?
CN I, olfactory
38
What is the olfactory bulb?
A ganglion containing the cell bodies of the second neurones of CN I
39
Where are the olfactory bulbs?
On either side of the crista galli
40
Which nerves supply the nasal cavity?
CNVI superioposterior
| CNV2 posteroinferior
41
From which arteries do the maxillary and facial arteries come from.
Ext and int carotids
42
What does the ophthalmic artery branch into?
Anterior and posterior ethmoidal arteries
43
Which arteries does the maxillary artery give off?
sphenopalatine and great palatine
44
What artery does the facial artery give off?
The lateral nasal branch of the facial artery
45
What is Kiesselbach's / Little's area?
Arterial anastomoses on the nasal septum which is a common site for nosebleeds.
46
How many conchae are in the nose and what are they called?
3
| Superior, middle, inferior
47
What is the purpose of the conchae?
Increase surface area and increase turbulence to warm/humidify air
48
What are meatuses?
Spaces under each concha
49
Where is the sphenoethmoidal recess?
The superior part of the nasal cavity
50
How should an NG tube be placed and what needs to be considered?
Avoid Kiesselbach's area to avoid epistaxis
Passed through nasopharynx without going into the Eustachian tube
Run through oeseophagus (not trachea)
10cm past GOJ
Radiograph to confirm placement
51
What are the paranasal sinuses?
Air filled spaces within bones
52
What are the paranasal sinuses lined with?
Mucous secreting respiratory mucosa
53
Where do the frontal sinuses drain to?
Middle meatus
54
Where do ethmoidal air cells drain to?
Superior and middle meatuses
55
Where do sphenoidal sinuses drain to?
Sphenoethmoidal recess
56
What is sinusitis?
Inflammation of the paranasal sinuses
57
What is the most common location of sinusitis?
Maxillary sinuses (Antra)
58
Why is the most common location of sinusitis the antra?
The ostia of this sinus is superiorly on the medial wall so mucous has to be drained against gravity
59
What procedure can result in maxillary sinusitis, why?
Tooth extraction as it may result in an oro-antral fistula allowing infection spread
60
What is the pterion?
The thinnest part of the skull. It is H shaped suture where frontal, parietal and temporal bones meet
61
What makes up the anterior fossa of the cranial cavity ?
Spenoid, ethmoid and frontal bones
62
What nerve comes out of the anterior fossa of the cranial cavity?
CN I, olfactory
63
Where is the cribiform plate of the ethmoid bone housed in the cranial cavity?
Anterior fossa
64
Which bones make up the middle cranial fossa?
Temporal and sphenoid
65
Which nerves come out of the middle cranial fossa?
CN II - VI
66
Which openings are present in the middle cranial fossa?
Optic canal, superior orbital fissure, foramen rotundum, foramen ovale, opening of carotid canal
67
Which bones make up the posterior cranial fossa?
Parietal and occipital
68
Which nerves come out of the posterior fossa?
CN VII-XII
69
Which openings are present in the posterior cranial fossa?
Internal acoustic meatus, jugular foramen and hypoglossal canal
70
What is the external ear?
The part of the ear from the auricle to the tympanic membrane via the external acoustic meatus
71
What is the middle ear?
From the tympanic membrane to the oval window, including the Eustachian tube
72
What is the function of the external ear?
To collect sound waves and amplify them to the tympanic membrane
73
What is the function of the middle ear?
To amplify sound and conduct it to the internal ear
74
What is the internal ear?
From the oval window to the internal acoustic meatus
75
What is the purpose of the internal ear?
Convert special sensory information into fluid waves, then APs
76
Name the three parts of the auricle.
Helix, tragus and ear lobe.
77
What is the sensory nerve nerve supply of the posterior helix?
C2, 3
78
What is the sensory nerve supply of the medial part of the anterior helix?
CN V3, mandibular division of the trigeminal nerve
79
What is the sensory nerve supply of the tragus?
CN X, vagus with some CN VII, facial
80
What is the sensory supply of the tympanic membrane?
Mostly CNV3, mandibular division of the trigeminal nerve?
81
Which lymph nodes does the auricle drain to?
Patorid, mastoid and superficial then all to deep cervical then thoracic duct then venous angle
82
What is the external ear made up of?
The temporal bone and hyaline cartilage
83
Describe the blood supply of the cartilage of the auricle?
Avascular
84
Which glands produce ear wax?
Ceruminous glands
85
What is the sensory supply of the nasopharynx, oropharynx and tonsils?
CNIX, glossopharyngeal
86
Which type of joint articulates the ossicles?
Synovial
87
Name the three ossicles.
Incus, stapes and malleus
88
What is the umbo?
The central, most inverted part of the ear drum
89
How is the umbo created?
By the handle of the malleus adhering to the internal tympanic membrane.
90
Which bone fits into the oval window?
The stapes
91
What is the area past the tympanic membrane called?
Tympanic cavity proper
92
What is superior to the tympanic cavity proper?
Epitympanic recess
93
What does the Eustachian tube connect?
Middle ear to the nasopharynx
94
What is a down-side of the Eustachian tube?
Easy to spread infection
95
What is the aditus?
A doorway into the mastoid antrum from the epitympanic recess
96
Where does the facial nerve come off the brainstem?
Between the pons and the medulla
97
Describe the route of the facial nerve from brainstem to middle ear.
Comes off of brainstem; passes into the internal acoustic meatus in the posterior cranial fossa; through facial canal in petrous temporal bone; stylomastoid foramen; middle ear
98
What is the petrous part of the temporal bone?
pyramid-shaped and is wedged in at the base of the skull between the sphenoid and occipital bones
99
What nerve supplies the stapedius?
CN VII
100
What nerve supplies the taste buds of the anterior 2/3rds of the tongue?
Chorda tympani, branch of CNVII, facial
101
Which nerve give parasympathetic innervation to the submandibular and sublingual glands?
Chorda tympani, branch of CN VII, facial
102
Which muscle of facial expression moves the forehead?
Frontalis
103
Which muscle of facial expression moves the eye?
Orbicularis occuli
104
Which muscle of facial expression moves the mouth?
Orbicularis oris
105
In what scenario is the buccal fat pad lost?
Malnutrition
106
What does the otic capsule contain?
Bony labyrinth which is filled with perilymph
107
What makes up the bony labyrinth?
Semi-circular canals and the cochlea
108
What is the cupula?
Apex of the cochlea
109
What does the perilymph contain?
Membranous labyrinth
110
What is the membranous labyrinth?
Communicating sacs and ducts containing endolymph
111
Describe the transmission of sound in the ear.
Sound makes tympanic membrane vibrate
Vibrations transmitted along ossicles
Base of stapes in oval window vibrates to create a pressure wave in the perilymph
Hair cells in the cochlea move which releases a neurotransmitter
AP transmitted to the brain by cochlear nerve
112
What happens to the pressure waves formed on sound transmission?
They descend and revert to vibrations which are dampened at the round window
113
Where is the round window?
Below the oval window
114
Where do CNVII and CNVII connect?
Junction between the pons and medulla oblongata
115
What does the mandibular prominence give rise to?
Lower lip
116
What does the frontonasal prominence give rise to?
Bridge and nasal septum
117
What do the medial nasal prominences give rise to?
Crest and tip of nose
118
On which prominence do the medial and lateral nasal swellings come from, and when?
Fronotnasal, week 5
119
Which segment gives rise to the philtrum?
Intermaxillary segment
120
What is the anterior border of the oral cavity?
Teeth
121
What is the posterior border of the oral cavity?
Oropharynx
122
What is the superior border of the oral cavity?
Hard and soft palates
123
Which muscles are in the floor of the mouth?
Mylohyoid, geniohyoid, anterior belly of digastric
124
What connects the tongue to the mucosa of the floor?
Frenulum
125
What are the spaces on either side of the frenulum?
Sublingual folds
126
Where are the minor salivary glands?
Oral mucosa, lips, cheeks, palate
127
How does the parotid duct get to the buccal mucosa?
Crosses the masseter, through the buccinators, opens on the parotid papilla on the buccal mucosa
128
Which nerve supplies parasympathetic secretomotor innervation to the parotid gland?
CN IX, glossopharyngeal
129
Which nerve supplies parasympathetic secretomotor innervation to the submandibular and sublingual glands?
CNVII, facial
130
Describe the innervation of the tongue.
Anterior 2/3rds: CNVII for special sensory, CNV3 for general sensory
Posterior 1/3rd: general and special sensory from CN IX, glossopharyngeal
131
Which structure is the origin of the thyroid gland?
Foramen caecum
132
Name the extrinsic tongue muscles
Styloglossus, hyoglossus, genioglossus
133
How many pairs of intrinsic tongue muscles are there?
4
134
Describe the course of the hypoglossal nerve to the muscles of the tongue
Medulla oblongata to hypoglossal canal in the posterior cranial fossa
Through occipital bone, descends in the carotid sheath
Passes anteriorly to the lateral aspect of the tongue
135
How do you test CN XII, hypoglossal nerve function?
Get patient to stick tongue out, in midline good, if pathology it deviates toward the affected side
136
Name the 5 pairs of muscles in the soft palate
Levator veli palatini, tensor veli palatini, palatoglossus, palatopharyngeus, musculus uvulae
137
What is the function of levator veli palatini?
Lift the soft palate
138
What is the function of tensor veli palatini?
Tense the soft palate
139
Which nerve supplies the muscles of the soft palate?
CNX, vagus - except tensor veli palatini which is CNV3.
140
How to test nerve supply to soft palate?
Get patient to say "ahhh", damage to CNV3 or CNX will result in uvula deviating AWAY from pathological side
141
Which nerve innervates external layer on constrictor muscles in the pharynx?
CNX (pharyngeal plexus of)
142
Where do all of the constrictor muscles on the pharynx insert?
Midline raphe
143
Name the longitudinal muscles of the pharynx.
Stylophayngeus (styloid process) palatopharyngeous (palate), salpingopharyngeus (cartilage of pharyngotympanic tube)
144
Which nerve innervates palatopharyngeus and salpingopharyngeus?
CNX
145
Which nerve innervates stylopharyngeus?
CN IX
146
Which tonsils are included in Waldeyer's ring?
Adenoid (nose) tonsil; tubual tonsils (Eustachian tube); palate-associated-lymphoid-tissue; lingual tonsil (post 1/3 tongue) and palatine tonsil (tonsillar fossa)
147
At what level is the larynx?
C4-C6
148
What is the function of the pharynx?
Maintain patency of URT, prevent entry of foreign bodies into LRT and produce sound
149
Which layer of fascia in the pharynx in?
Pre-tracheal fascia
150
What other structures are in the pre-tracheal fascia?
Thyroid gland, trachea, oesophagus, pharynx and recurrent laryngeal nerves
151
What are the true vocal cords?
Vocal processes of the arytenoid cartilage to thyroid cartilage
152
What are the false vocal cords?
Arytenoid cartilage to the epiglottis
153
What is the rima glottidis?
Space between the true vocal cords
154
What is the function of the intrinsic muscles of the larynx?
To move the vocal cords
155
What nerve innervates the intrinsic muscles of the larynx?
CN X, vaugs
156
What happens when the vocal cords tense?
Pitch increases
157
What happens when the vocal cords adduct?
Sound is quieter
158
Which muscles contract to abduct the cords?
Posterior crico-arytenoids
159
Which muscles contract to adduct the cords?
Arytenoids
160
Which muscles contract in whispering?
Lateral cricothyroids
161
Where would a supra-glottis tumour drain?
Superior deep cervical nodes
162
How do glottis tumours present?
Voice changes and airway obstruction
163
Where would a sub-glottis tumour drain?
Paratracheal nodes
164
What happens on controlled expiration?
Contraction of anterolateral abdo wall, contraction of inspiratory intercostal muscles
This builds subglottal pressure
165
What is required for phonation?
Subglottal pressure to reach a set threshold
166
What are the intrinsic muscles supplied by?
inferior laryngeal nerve
167
What is mucosa above the vocal folds innervated by?
Internal laryngeal nerve
168
What is mucosa below the vocal folds innervated by?
Recurrent laryngeal
