Region 10 - Neck Flashcards
1
Q
What muscle divides the neck into anterior and posterior triangles?
A
Sternocleidomastoid
2
Q
What is the anterior boundary of the anterior triangle of the neck?
A
Imaginary median line of neck
3
Q
What is the posterior boundary of the anterior triangle of the neck?
A
Anterior border of SCM
4
Q
What is the superior boundary/base of the anterior triangle of the neck?
A
Inferior border of mandible
5
Q
What is the apex of the anterior triangle of the neck?
A
Jugular notch at manubrium
6
Q
What is the roof of the anterior triangle of the neck?
A
Subcutaneous tissues and platysma
7
Q
What is the floor of the anterior triangle of the neck?
A
Pharynx
Larynx
Thyroid
8
Q
What is the sub-mental division of the anterior triangle of the neck bounded by?
A
Chin (superiorly)
Body of hyoid (inferiorly)
Anterior bellies of digastric muscles (laterally)
Mylohyoid muscles (floor)
9
Q
What is the submandibular division of the anterior triangle of the neck bounded by?
A
Inferior border of mandible (superiorly)
The anterior and posterior bellies of the digastric muscle
Mylohyoid and hyoglossus muscles (floor)
10
Q
What are the contents of the sub-mental division?
A
Submental lymph nodes
Beginning of anterior jugular vein
11
Q
What are the contents of the submandibular division?
A
Submandibular salivary gland
Lymph nodes
Facial artery and vein
Hypoglossal nerve
12
Q
What are the boundaries of the carotid triangle of the anterior triangle of the neck?
A
Superior belly of omohyoid (anteriorly)
Posterior belly of digastric (superiorly)
Anterior border of SCM (posteriorly)
13
Q
What are the contents of the carotid triangle?
A
Branching of common carotid into: - External carotid artery (anterior) - Internal carotid artery Branches of external carotid artery Internal jugular vein Nerves: - Hypoglossal - Accessory - Vagus Deep cervical nodes
14
Q
Within what structure are the neurovascular structures contained in the carotid triangle?
A
Carotid sheath:
- Common and internal carotid arteries (lie medially)
- Internal jugular vein (lies laterally)
- Vagus nerve (lies posteriorly
15
Q
What structures within the carotid triangle are not within the carotid sheath?
A
External carotid artery and its branches
Accessory nerve
Hypoglossal nerve
Deep cervical nodes
16
Q
What are the boundaries of the muscular triangle of the anterior triangle of the neck?
A
Superior belly of omohyoid (superiorly)
Anterior border of SCM (posteriorly)
Median line of neck (anteriorly)
17
Q
What are the contents of the muscular triangle?
A
Sternohyoid
Sternothyroid
(both form its floor)
18
Q
What structures lie beneath the floor of the muscular triangle?
A
Thyroid
Larynx
Trachea
Oesophagus
19
Q
What are the origins of platysma?
A
Deep fascia covering superior parts of:
- Deltoid
- Pectoralis major
Clavicle
20
Q
What is the insertion of platysma?
A
Inferior border of mandible
21
Q
What is the innervation to platysma?
A
Facial nerve
22
Q
What are the functions of platysma?
A
Releases pressure on superficial veins Depresses mandible Draws corners of mouth down (frown) Facial expressions of: - Tension - Stress
23
Q
What veins lie in the anterior triangle of the neck?
A
Tributaries to external jugular vein (superficial to SCM)
Internal jugular vein (deep to SCM)
Anterior jugular vein:
- In midline
24
Q
What veins in the anterior triangle of the neck may be absent?
A
Anterior jugular veins
25
What are the main tributaries to the IJV?
```
Inferior petrosal sinus
Facial vein
Lingual vein
Superior and middle thyroid veins
Occipital vein (sometimes)
Pharyngeal veins
```
26
What can the anterior jugular veins form superior to the manubrium?
Jugular venous arch
27
Where do the anterior jugular veins drain to?
External jugular vein usually
28
Where do the external jugular veins drain to?
Subclavian veins
29
What are the tributaries to the cervical plexus?
Anterior rami of C1-C4
30
The cervical plexus is joined by loops that lie anterior to what structures?
Levator scapulae
| Middle scalene
31
What covers the cervical plexus?
Prevertebral layer of deep cervical fascia
32
What are the cutaneous sensory branches of the cervical plexus?
```
Lesser occipital (C2)
Great auricular (C2 and C3)
Transverse cervical (C2 and C3)
Supraclavicular (C3 and C4)
```
33
What are the motor branches of the cervical plexus?
Ansa cervicalis (C1-C3)
Phrenic nerve (C3-C5)
Nerves to:
- Levator scapulae
34
Proprioception to which nerves is supplied by the cervical plexus?
SCM
| Trapezius
35
What muscles is the ansa cervicalis branch of the cervical plexus responsible for supplying?
Sternohyoid
Sternothyroid
Omohyoid
36
How does the nerve supply to thyrohyoid reach the muscle?
A branch from C1 ventral ramus travels with the hypoglossal nerve
37
How does the branch from C1 ventral ramus reach the ansa cervicalis?
Travels initially with the hypoglossal nerve
38
Where is the suprahyoid region?
Between:
- Hyoid bone AND
- Skull/Mandible
39
Where is the infrahyoid region?
Between:
- Hyoid bone AND
- Sternum/Thyroid cartilage
40
What are the suprahyoid muscles?
Mylohyoid
Geniohyoid
Stylohyoid
Digastric
41
What are the functions of the suprahyoid muscles?
Raise hyoid bone
| Depress mandible
42
What is the innervation to the suprahyoid muscles?
```
Facial nerve:
- Posterior belly of digastric
- Stylohyoid
Mandibular division of trigeminal nerve:
- Anterior belly of digastric
- Mylohtoid
C1 via hypoglossal nerve:
- Geniohyoid
```
43
What are the infrahyoid muscles?
Sternohyoid
Omohyoid
Sternothyroid
Thyrohyoid
44
What are the functions of the infrahyoid muscles?
Depress:
- Hyoid bone
- Thyroid cartilage
45
What is the innervation to the infrahyoid muscles?
```
Ansa cervicalis:
- Sternohyoid
- Omohyoid
- Sternothyroid
C1 via hypoglossal nerve:
- Thyrohyoid
```
46
What are the origins of the common carotid artery?
Right from brachiocephalic trunk
| Left from arch of aorta
47
What are the anterior branches of the external carotid artery?
Superior thyroid artery
Lingual artery
Facial artery
48
What does the superior thyroid artery supply?
Thyroid gland
Infrahyoid muscles
SCM
Larynx (via superior laryngeal artery)
49
What does the lingual artery supply?
Posterior tongue
50
What are the branches of the lingual artery?
Deep lingual artery
| Siblingual artery
51
What are the branches of the facial artery?
Ascending palatine artery
Tonsillar artery
Submental artery
52
How does the facial artery enter the face?
Hooks around the mid-inferior border of the mandible
53
What do the recurrent laryngeal branches of the vagus nerve hook around?
Left around arch of aorta
| Right around right subclavian artery
54
What is the structure of the thyroid gland?
```
External capsule
2 lobes running between:
- Thyroid cartilage
- 6th tracheal ring
Isthmus connecting lobes anterior to tracheal rings 2 or 3
```
55
What is the arterial supply to the thyroid gland?
inferior thyroid artery from thyrocervical trunk of subclavian artery
Superior thyroid artery from ECA
56
What is the venous drainage of thyroid gland?
Superior and middle thyroid veins:
- Drain to ipsilateral IJV
Inferior thyroid veins:
- Both drain to left brachicephalic vein
57
What does the submandibular salivary gland lie?
Part is inferior to mylohyoid
| Part in floor of mouth superior mylohyoid
58
Where does the duct for each submandibular gland open?
Between 1st and 2nd lower incisors (either side of frenulum)
59
What is the innervation to the submandibular glands?
Facial nerve
60
What are the borders of the posterior triangle of the neck?
Posterior border of SCM (anterior)
Anterior border of trapezius (posterior)
Clavicle (base)
Apex:
- Where SCM and trapezius meet on superior nuchal line
Investing layer of deep cervical fascia (roof)
Muscles covered by prevertebral layer of deep cervical fascia (floor)
61
What are the non-muscular contents of the posterior triangle of the neck?
External jugular vein
Roots of brachial plexus
Accessory nerve
Cervical and supraclavicular lymph nodes
62
What are the muscular contents of the posterior triangle of the neck?
Anterior scalene (inferior part)
Middle and posterior scalenes
Splenius capitis
Levator scapulae
63
What are the superior attachments of the SCM?
Lateral surface of mastoid process of temporal bone
| Lateral half of superior nuchal line
64
What are the inferior attachments of the SCM?
Sternal head:
- Anterior surface of manubrium
Clavicular head:
- Superior surface of medial 1/3 of clavicle
65
What is the innervation to SCM?
Motor = Spinal accessory nerve
| Pain and proprioception = C2 and C3
66
What are the functions of SCM working unilaterally?
Flexes neck to ipsilateral side
| Rotates face superiorly to contralateral side
67
What are the functions of SCM working bilaterally?
Extends neck at atlanto-occipital joints
Flexes cervical vertebrae
Protracts chin
68
What are the origins of trapezius?
Medial 1/3 of superior nuchal line
External occipital protuberance
Nuchal ligament
Spinous processes of C7-T12, lumbar and sacral vertebrae
69
What are the insertions of trapezius?
Lateral 1/3 of clavicle
Acromion
Spine of scapula
70
What is the innervation to trapezius?
Motor = Spinal accessory nerve
| Pain and proprioception = C3 and C4
71
What are the functions of trapezius?
```
Ascending part = Depresses scapula
Transverse part = Retracts scapula
Descending part:
- Elevates scapula
- Rotates glenoid cavity
Hold scapula in place while weightlifting
```
72
What muscles form the floor of the posterior triangle?
Omohyoid
| Splenius capitis
73
What are the functions of splenius capitis?
Extends neck
| Rotates neck
74
What is the innervation to splenius capitis?
Posterior rami C3 and C4
75
What are the origins of levator scapulae?
Transverse processes of:
- Atlas
- Axis
- C3 and C4
76
What are the insertions of levator scapulae?
Medial scapular border between:
- Superior angle of scapula AND
- Medial end of scapular spine
77
What are the functions of levator scapulae?
Controls scapular position
Elevates shoulder (with trapezius)
Can laterally flex neck ipsilaterally if shoulder fixed
78
What is the innervation to levator scapulae?
```
Cervical nerves (C3 and C4)
Dorsal scapular nerve (C5)
```
79
What are the origins of the scalene muscles?
Transverse processes of:
- C3-C6 (anterior)
- C2-C7 (middle)
- C4-C6 (posterior)
80
What are the insertions of the scalene muscles?
Rib 1:
- Scalene tubercle (anterior)
- Behind subclavian artery groove (middle)
Rib 2 (posterior)
81
What is the innervation to the scalene muscles?
Anterior rami C4-C7 (anterior)
Anterior rami C3-C7 (middle)
Anterior rami C5-C7 (posterior)
82
What are the functions of the scalene muscles?
Flex neck (bilaterally)
Laterally flex neck (unilaterally)
Elevate upper ribs
83
What is the shape of the upper end of the pharynx at the base of the skull?
Funnel-shaped
84
At what level does the pharynx join the oesophagus?
C6
85
What is the epithelium of the pharynx?
```
Superiorly = Ciliated columnar
Inferiorly = Stratified squamous
```
86
What does the fibrous layer underlying the epithelium of the pharynx connect it to?
Base of skull
| Submucosa of oesophagus
87
What layer lies under the fibrous layer of the pharynx?
Muscular layer:
- Circular constrictor muscles
- Longitudinal muscles
88
Where is the nasopharynx?
Behind nasal cavities
| Above soft palate
89
What structures form the roof of the nasopharynx?
Sphenoid bone
Occipital bone
Pharyngeal tonsil
90
What structure forms forms the floor of the nasopharynx?
Soft palate (pharyngeal isthmus)
91
What structures form the posterior wall of the nasopharynx?
Roof structures at the level of C1
92
What structures form the lateral wall of the nasopharynx?
Pharyngotympanic tube
| Salpingopharyngeal fold
93
Where is the oropharynx?
From soft palate to upper border of epiglottis
94
What forms the roof of the oropharynx?
Soft palate
95
What forms the floor of the oropharynx?
Posterior 1/3 tongue
Lingual tonsil
Glossoepiglottic folds
96
What forms the posterior wall of the oropharynx?
C2/C3 level
97
What forms the lateral walls of the oropharynx?
```
Palatoglossal folds (anteriorly)
Palatopharyngeal folds (posteriorly)
Palatine tonsil between the two
```
98
Where is the laryngopharynx?
Behind larynx and laryngeal opening
99
What lies posterior to the laryngopharynx?
C3-C6 vertebrae
100
What is the laryngopharynx supported by laterally?
Thyroid cartilage
Aryepiglottic fold
Thyrohyoid membrane
101
What are the origins of the superior constrictor of pharynx?
```
Posterior aspect of medial pterygoid plate
Pterygoid hamulus
Pterygomandibular ligament
Mandible
Side of tongue
```
102
What are the insertions of the superior constrictor of pharynx?
Pharyngeal tubercle of occipital bone
Midline fibrous raphe
Middle constrictor
103
What is the innervation to the superior constrictor of pharynx?
CN X in pharyngeal plexus
104
What are the functions of the superior constrictor of pharynx?
Upper fibres:
- Pull posterior pharyngeal wall anteriorly to close off nasopharynx
Propels food to middle constrictor
105
What does the gap between superior and middle constrictors of pharynx allow passage of?
Stylopharyngeus
CN IX
Stylohyoid ligament
106
What are the origins of the middle constrictor of pharynx?
```
Stylohyoid ligament (lower part)
Greater and lesser cornu of hyoid
```
107
What are the insertions of the middle constrictor of pharynx?
Midline fibrous raphe
| Blends with superior and inferior constrictors of pharynx
108
What is the innervation to the middle constrictor of pharynx?
CN X in pharyngeal plexus
109
What is the function of the middle constrictor of pharynx?
Propels food to inferior constrictor of pharynx
110
What does a gap between the middle and inferior constrictors of pharynx allow the passage of?
Internal laryngeal nerve
| Superior laryngeal artery and vein
111
What are the origins of the inferior constrictor of pharynx?
Lamina of:
- Thyroid cartilage
- Cricoid cartilage
112
What are the insertions of the inferior constrictor of pharynx?
Midline fibrous raph
| Blends with middle constrictor and oesophagus
113
What is the thyropharyngeus?
The superior part of the inferior constrictor of pharynx
114
What direction do the fibres of thyropharyngeus run?
Obliquely
115
What is the innervation to thyropharyngeus?
CN X in pharyngeal plexus
116
What is the function of thyropharyngeus?
Propels food into oesophagus
117
What is the cricopharyngeus?
Inferior part of the inferior constrictor of pharynx
118
What direction do the fibres of cricophayngeus run in?
Transversely
119
What is the innervation to cricopharyngeus?
External laryngeal nerve (CN X)
120
What is the function of cricopharyngeus?
Acts as a sphincter:
| - Prevents entry of air between acts of swallowing
121
What does the gap inferior to the inferior constrictor of pharynx allow passage of?
Allows passage of structures superiorly into larynx:
- Recurrent laryngeal nerve
- Inferior laryngeal artery
122
What is the origin and insertion of stylopharyngeus?
```
Origin = Styloid process
Insertion = Posterior border of thyroid cartilage
```
123
What is the course of stylopharyngeus?
Runs across ICA
| Passes between superior and middle constrictors
124
What is the function of stylopharyngeus?
Elevates larynx and pharynx during swallowing
125
What is the innervation to stylopharyngeus?
CN IX
126
What is the origin and insertion of salpingophayngeus?
```
Origin = Cartilage of pharyngotympanic tube
Insertion = Blends with palatopharyngeus
```
127
What is the function of salpingopharyngeus?
Elevates pharynx
128
What is the innervation to salpingopharyngeus?
CN X in pharyngeal plexus
129
What are the origins of palatopharyngeus?
Hard palate
| Palatin aponeurosis
130
What are the insertions of palatopharyngeus?
Posterior border of lamina of thyroid cartilage
| Side of pharynx and oesophagus
131
What is the function of palatopharyngeus?
Elevates pharynx
132
What is the innervation of palatopharyngeus?
CN X in pharyngeal plexus
133
What is the ring of lymphoid tissue?
```
Superiorly = Pharyngeal tonsil
Superolaterally = Tubal tonsils
Laterally = Lymph tissue along salpingopharyngeal folds
Inferolaterally = Palatine tonsils
Inferiorly = Lingual tonsil
```
134
The pharyngeal plexus supplies motor fibres from CN X to all pharyngeal and soft palate muscles. What are the exceptions?
Stylopharyngeus (CN IX)
Tensor veli palatini (CN V3)
Cricopharyngeus (External laryngeal nerve = CN X)
135
What nerve carries sensory fibres from the pharynx?
CN IX to pharyngeal plexus
136
What is the arterial supply to pharynx?
Pharyngeal branches from maxillary artery - Nasopharynx
Ascending pharyngeal artery:
- From 'deep'/medial surface of ECA
137
What is the venous drainage of the pharynx?
Pharyngeal veins to IJV
138
Where does lymph from the tonsils go?
Jugulodigastric node
139
Where do other pre-vertebral structures lie? (ie aside from the pre-vertebral [anterior] muscles)
Between:
- Muscle sheath covering longus colli and longus capitis (prevertebral fascia)
AND
- Carotid sheath
140
What are the attachments of longus capitis?
```
Superiorly = Occipital bone (base)
Inferiorly = Anterior tubercles of C3-C6 transverse processes
```
141
What is the function of longus capitis?
Flexion of head (nodding)
142
What is the innervation to longus capitis?
Ventral rami of C1-C3
143
What are the attachments of the inferior oblique part of longus colli?
```
Superiorly = Anterior tubercles of C5-C6 transverse processes
Inferiorly = Body of T2 and T3
```
144
What are the attachments of the superior oblique part of longus colli?
```
Superiorly = Anterior tubercle of C1
Inferiorly = Anterior tubercles of C3-C5 transverse processes
```
145
What are the attachments of the vertical part of longus colli?
```
Superiorly = Anterior aspects of C4-C6
Inferiorly = Anterior aspects of T1-T3
```
146
What is the function of longus colli?
Flexion of neck
147
What is the function of the inferior oblique part of longus colli?
Rotation to contralateral side
148
What is the innervation to longus colli?
Ventral rami of C2-C6
149
What are the attachments of rectus capitis anterior?
```
Superiorly = Occipital bone (anterior to condyles)
Inferiorly = Anterior surface of and root of transverse process of C1
```
150
What is the function of rectus capitis anterior?
Flexion of atlanto-occipital joint
151
What is the innervation to rectus capitis anterior?
Branches from loop between C1 and C2
152
What are the attachments of rectus capitis lateralis?
```
Superiorly = Jugular process of occipital bone
Inferiorly = Transverse process of C1
```
153
What is the function of rectus capitis lateralis?
Lateral flexion of head
154
What is the innervation to rectus capitis lateralis?
Branches from loop between C1 and C2
155
What structure crosses rectus capitis lateralis?
IJV
156
Where does the sympathetic chain lie in the neck?
```
Posterior to ICA and CCA
Medial to CN X
Embedded in deep fascia between:
- Carotid sheath AND
- Fascia over longus colli and longus capitis
```
157
What are the cervical ganglia of the sympathetic chain?
Superior, middle and inferior
158
Where does the superior cervical ganglia lie?
Immediately below skull (~C1-C2)
159
Where do postsynaptic fibres from the superior cervical ganglia travel to and in what?
Travel in internal carotid nerve:
- Travel into carotid canal
- Forms internal carotid plexus
160
What do the grey rami communicantes from the superior cervical ganglia connect to?
C1-C4 ventral rami
161
What branches are given off from the superior cervical ganglia?
```
Branches to form plexuses on CCA and ECA
CN branches to CNs IX, X and XII
Pharyngeal branches:
- Pharyngeal plexus
- Joining CNs IX and X
```
162
What cardiopulmonary splanchnic nerve is given off from the superior cervical ganglia?
Superior cardiac nerve
163
At what level are the middle cervical ganglia?
Cricoid cartilage (~C6)
164
What structure are the middle cervical ganglia related to?
Loop of inferior thyroid artery
165
What do the grey rami communicantes from the middle cervical ganglia connect to?
C5 and C6 ventral rami
166
What branches do the middle cervical ganglia give off?
Thyroid branches:
- Run along inferior thyroid artery
Middle cardiac nerve (cardiac plexus)
167
The middle cervical ganglia is often connected to the inferior cervical ganglia by more than 2 nerve bundles. Where does the anterior bundle pass?
Passes anterior to 1st part of subclavian artery then behind it:
- Ansa subclavia
168
What does the inferior cervical ganglia usually fuse with? What is this structure called?
1st thoracic ganglion = Stellate ganglion
169
Where do the inferior cervical ganglia lie?
Posterior to vertebral artery
Between:
- Transverse process of C7 AND
- Head of first rib
170
What do the grey rami communicantes from the inferior cervical ganglia connect to?
C7 and C8 ventral rami
171
What branches do the inferior cervical ganglia give off?
Arterial branches to:
- Subclavian artery
- Vertebral artery
Inferior cardiac nerve (to cardiac plexus)
172
What structures lie anterior to the larynx?
Infrahyoid muscles
| Isthmus of thyroid
173
What structures lie lateral to the larynx?
Lobes of thyroid
| Carotid sheath
174
What neurovascular structures is the larynx related to?
Superior and inferior thyroid arteries
| Recurrent laryngeal nerves
175
What is the larynx responsible for?
Voice production
176
How many cartilages make up the larynx?
9
177
What type of cartilage makes up the larynx? What is the exception?
All hyaline
| Except epiglottis - Elastic cartilage
178
What is the laryngeal prominence?
Where the inferior 2/3 of the laminae of the thyroid cartilages fuse anteriorly
179
What structure lies superior to the laryngeal prominence?
V-shaped superior thyroid notch
180
How does the thyroid cartilage connect to the hyoid?
Thyrohyoid membrane:
- Thickened medially as median thyrohyoid ligament
- Thickened laterally as lateral thyrohyoid ligament
181
What does an oblique line on the anterolateral surface of each thyroid cartilage act as the attachment for?
Sternothyroid muscle
Thyrohyoid muscle
Inferior constrictor of pharynx
182
What lies at either end of the oblique line on the anterolateral surface of each thyroid cartilage?
Superior tubercle
| Inferior tubercle
183
Why is the cricoid cartilage described as having a signet ring shape?
Anterior part is the arch (narrower)
Posterior part is the lamina:
- Broader
- Has a central ridge
184
What distinguishing characteristic does the cricoid cartilage have other all other laryngeal or tracheal cartilages?
Only complete ring of cartilage to encircle any part of airways
185
What are the facets on the superior aspects of the posterior part of the cricoid cartilage for?
Articulation with arytenoid cartilages
186
What do the vocal processes on the arytenoid cartilages do?
Allow attachment of the vocal ligament
187
Where are the vocal processes on the arytenoid cartilages?
Anteroinferiorly
188
Where are the corniculate cartilages?
In posterior part of aryepiglottic folds
| Attached to apices of arytenoid cartilages (superior)
189
Where are the cuneiform cartilages?
Within aryepiglottic folds:
| - Support the folds
190
What are the connections of the epiglottis?
```
Anteriorly:
- Body of hyoid
- Posterior surface of thyroid cartilage
Laterally:
- Arytenoid cartilages (via aryepiglottic fold)
```
191
What structure does the mucous membrane covering the epiglottis reflect onto? What does this form?
Reflects onto posterior surface of tongue:
- Median glossoepiglottic fold
- Lateral glossoepiglottic folds
192
Where does the quadrangular membrane/ligament run?
Arytenoid cartilages to epiglottis
193
What do the free edges of the quadrangular membrane form?
Superiorly = Aryepiglottic fold
Inferiorly = Vestibular ligament:
- ie False vocal fold
194
What does the cricothyroid membrane attach to?
Cricoid cartilage
Thyroid cartilage
Arytenoid
195
What does the cricothyroid membrane form via its connection as its free edge to the arytenoid cartilages?
Vocal ligaments:
| - ie True vocal folds
196
Where do the vestibular folds lie in relation to the true vocal folds?
Superiorly
197
What are the true vocal folds attached to?
```
Anteriorly = Thyroid cartilage
Posteriorly = Arytenoid cartilages
```
198
Movements of what structures create individual sounds and words?
Lips
Cheeks
Tongue
199
How do the suprahyoid muscles affect the larynx?
Elevate larynx
200
How do the infrahyoid muscles affect the larynx?
Depress larynx
201
What assists the suprahyoid muscles in their action on the larynx?
Stylopharyngeus
Salpingopharyngeus
Palatopharyngeus
202
What assists the infrahyoid muscles in their action on the larynx?
Its elastic recoil
203
What is the origin of the cricothyroid muscle?
Anterolateral cricoid cartilage
204
What are the insertions of the cricothyroid muscle?
Lamina of thyroid cartilage
| Inferior cornu of thyroid cartilage
205
What are the parts of the cricothyroid muscle?
Straight part - Lies more anteriorly
| Oblique part - Lies anterolaterally
206
What are the functions of the cricothyroid muscle?
Tenses vocal folds
| Elongates vocal folds
207
How does the cricothyroid muscle affect the vocal folds?
Increases distance between thyroid cartilage and vocal processes of arytenoid cartilages by:
- Tilting thyroid cartilage forwards
- Tilting cricoid cartilage backwards
208
What is the innervation to cricothyroid?
External laryngeal nerve (CN X)
209
What are the origins of the thyro-arytenoid muscle?
Inner surface of angle of thyroid cartilage
| Cricothyroid ligament
210
What is the insertion of the thyro-arytenoid muscle?
Anterolateral surface of arytenoid cartilages
211
What can the upper fibres of the thyro-arytenoid muscle, which run alongside the vocal ligament, be called?
Vocalis muscle
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What is the function of the thyro-arytenoid muscle?
Pull arytenoids forwards towards thyroid cartilage:
- Shortens vocal ligaments
- Relaxes vocal folds
213
What is the innervation to the thyro-arytenoid muscle?
Recurrent laryngeal nerve (CN X)
214
What is the origin and insertion of the posterior cricoarytenoid muscle?
```
Origin = Posterior surface of lamina of cricoid
Insertion = Muscular process of arytenoid
```
215
What is the function of the posterior cricoarytenoid muscle?
Pulls muscular processes of arytenoid cartilages backwards:
- Rotates vocal processes laterally
- Vocal fold abduction
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What is the innervation to the posterior cricoarytenoid muscle?
Recurrent laryngeal nerve (CN X)
217
What is the origin and insertion of the lateral cricoarytenoid muscle?
```
Origin = Upper edge of arch of cricoid cartilages
Insertion = Muscular process of arytenoid cartilage
```
218
What is the function of the lateral cricoarytenoid muscle?
Pulls muscular processes forwards:
- Rotates vocal processes medially
- Vocal fold adduction
219
What is the innervation to the lateral cricoarytenoid muscle?
Recurrent laryngeal nerve (CN X)
220
What is the origin and insertion of the oblique arytenoid muscle?
```
Origin = Muscular process of one arytenoid cartilage
Insertion = Apex of contralateral arytenoid cartilage
```
221
What do some of the fibres of the oblique arytenoid muscles form?
Aryepiglottic muscles in aryepiglottic fold
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What is the function of the oblique arytenoid muscles?
Act as a sphincter of the laryngeal inlet by adducting vocal folds
223
What is the innervation to the oblique arytenoid muscle??
Recurrent laryngeal nerve (CN X)
224
What is the origin and insertion of the transverse arytenoid muscles?
```
Origin = Posterior and medial surfaces of arytenoid cartilages
Insertion = Contralateral arytenoid cartilage
```
225
What is the function of the transverse arytenoid muscles?
Close the posterior part of rima glottidis
226
What is the innervation to the transverse arytenoid muscles?
Recurrent laryngeal nerve (CN X)
227
Where does the superior laryngeal nerve arise?
From inferior vagal ganglion at superior end of carotid triangle
228
Where does the superior laryngeal nerve bifurcate? What does it bifurcate into?
Within carotid sheath into:
- Internal laryngeal nerve
- External laryngeal nerve
229
What does the internal laryngeal nerve pierces? With what?
Thyrohyoid membrane:
| - With superior laryngeal artery
230
What is the function of the internal laryngeal nerve?
Sensory to;
- Laryngeal mucous membrane
- Including superior surface of vocal folds
ANS fibres
231
What is the course of the external laryngeal nerve?
Descends posterior to sternothyroid muscle:
- With superior thyroid artery
Lies on then pierces inferior constrictor muscle
232
What is the function of the external laryngeal nerve?
Motor fibres to:
- Inferior constrictor
- Cricothyroid
233
What is the inferior laryngeal nerve a continuation of?
Recurrent laryngeal nerve
234
How does the inferior laryngeal nerve enter the larynx?
Passes:
- Deep to inferior border of inferior constrictor
- Medial to lamina of thyroid cartilage
235
What are the functions of the inferior laryngeal nerve?
Motor innervation to all intrinsic laryngeal muscles:
- Except cricothyroid
Sensory fibres to infraglottic cavity
236
What is the course of the superior laryngeal artery?
Branches from superior thyroid artery
| Pierces thyrohyoid membrane
237
What does the superior laryngeal artery supply?
Internal surface of larynx
| Cricothyroid muscle
238
What is the course of the inferior laryngeal artery?
Branches from inferior thyroid artery
| Accompanies inferior laryngeal nerve
239
What does the inferior laryngeal artery supply?
Mucous membrane and muscles of inferior part of larynx
240
What is the venous drainage of the larynx?
```
Superior laryngeal veins:
- Into superior thyroid veins
- Into IJV (ipsilaterally)
Inferior laryngeal veins:
- Into inferior thyroid veins OR Venous plexus on trachea
- Into left brachiocephalic vein
```
241
What is the lymphatic drainage of the larynx superior to the vocal folds?
Accompany superior laryngeal artery through thyrohyoid membrane
Drain to superior deep cervical nodes
242
What is the lymphatic drainage of the larynx inferior to the vocal fodls?
Drain to:
- Pretracheal nodes
- Paratracheal nodes
Eventualls drains to inferior deep cervical nodes
