Anatomy - The Internal Larynx and Pharynx Flashcards
1
Q
What nerve(s) are related to the superior thyroid arteries?
A
The external laryngeal nerves.
2
Q
What nerve(s) are related to the inferior thyroid arteries?
A
The recurrent laryngeal nerve crosses the inferior thyroid artery.
3
Q
How many parathyroid glands are there?
A
4.
4
Q
Where are the parathyroid glands located?
A
Posterior surface of thyroid glands.
5
Q
How are the parathyroid glands developed?
A
From the pharyngeal pouches.
6
Q
Name 3 functions of the larynx.
A
- Phonation. 2. Cough reflex. 3. Protection of the lower respiratory tract.
7
Q
What is the epithelium of the vocal folds? and why?
A
Stratified squamous epithelium. This is more robust and can withstand the vibrations and wear and tear.
8
Q
What is the blood supply to the larynx?
A
Superior and inferior laryngeal arteries (branches of the thyroid arteries).
9
Q
What does the recurrent laryngeal nerve supply?
A
Motor innervation to intrinsic muscles of the larynx (except cricothyroid).
10
Q
What does the internal branch of the superior laryngeal nerve supply?
A
Sensory innervation to laryngopharynx and larynx.
11
Q
What does the external branch of the superior laryngeal nerve supply?
A
Motor innervation to the cricothyroid muscle.
12
Q
Name the 3 unpaired cartilages in the larynx.
A
- Epiglottis (elastic cartilage). 2. Thyroid (hyaline cartilage). 3. Cricoid (hyaline cartilage).
13
Q
What do the two sheets of thyroid cartilage form in the midline?
A
The laryngeal prominence (Adam’s apple).
14
Q
What do the inferior horns of the thyroid cartilage articulate with?
A
They form a synovial joint with the cricoid cartilage.
15
Q
What do the superior horns of the thyroid cartilage articulate with?
A
The hyoid bone.
16
Q
What vertebral level is the inferior border of the larynx at?
A
C6.
17
Q
Name the 3 paired cartilages in the larynx.
A
- Arytenoid. 2. Cuneiform. 3. Corniculate.
18
Q
What do the arytenoid cartilages articulate with?
A
The base articulates with the cricoid cartilage and the apex articulates with the corniculate cartilages.
19
Q
Where are cuneiform cartilages located?
A
Within the ary-epiglottic folds. They strengthen the folds.
20
Q
What is the space between the vocal cords called?
A
Rima glottidis.
21
Q
What is the superior vestibular folds also known as?
A
False vocal folds.
22
Q
What are the extrinsic muscles of the pharynx?
A
The suprahyoids, infrahyoids and stylopharyngeus.
23
Q
What is the function of the extrinsic muscles of the larynx?
A
They move the larynx superiorly and inferiorly during swallowing.
24
Q
Name the 4 infrahyoid muscles.
A
- Omohyoid (scapula to hyoid). 2. Sternohyoid (sternum to hyoid). 3. Sternothyroid (sternum to thyroid). 4. Thyrohyoid (thyroid to hyoid).
25
What is the function of the intrinsic muscles of the larynx?
They control the shape of the rima glottidis, and the length and tension of the vocal folds.
26
What is the innervation of the intrinsic laryngeal muscles?
Recurrent laryngeal nerve.
27
What intrinsic laryngeal muscle is not innervated by the recurrent laryngeal nerve?
Cricothyroid.
28
What is the innervation of the cricothyroid muscle?
External branch of the superior laryngeal nerve.
29
What is the function of the cricothyroid muscles?
Stretches and tenses the vocal cords. Important for the creation of speech.
30
What is the function of the thyroarytenoid muscles?
Relaxes the vocal ligament, allowing for a softer voice.
31
What is the function of the posterior cricoarytenoid muscles?
Abduction of the vocal cords; the only muscles capable of widening the rima glottidis.
32
What is the function of the lateral cricoarytenoid muscles?
Adduction of the vocal folds; narrow the rima glottidis.
33
What is the function of the transverse arytenoids muscles?
Adduction of the arytenoid cartilages, narrows the laryngeal inlet.
34
What nerve passes through the parotid gland?
The facial nerve - Cn 7.
35
What are the 5 branches of Cn 7.
1. Temporal. 2. Zygomatic. 3. Buccal. 4. Mandibular. 5. Cervical.
36
Where does the pharynx extend from and to?
The base of the skull to the cricoid cartilage (C6).
37
What are the 3 sections of the pharynx called?
1. Nasopharynx. 2. Oropharynx. 3. Laryngopharynx.
38
What is the function of the pharyngeal constrictor muscles?
They contract sequentially to propel food into the oesophagus.
39
What is the origin of the superior constrictor?
Pterigoid plate and pterygomandibular raphe.
40
What is the origin of the middle constrictor?
Hyoid bone.
41
What is the origin of the inferior constrictor?
Thyroid and cricoid cartilages.
42
What is the innervation of the pharyngeal constrictors?
The pharyngeal branch of the Vagus nerve.
43
What is the function of the longitudinal pharyngeal muscles?
They shorten and widen the pharynx. They also elevate the pharynx during swallowing.
44
What are the 3 longitudinal pharyngeal muscles called?
1. Stylopharyngeus. 2. Salpingopharyngeus. 3. Palatopharyngeus.
45
What is the origin of the stylopharyngeus and what is its innervation?
Origin: Styloid process of temporal bone. Innervation: Glossopharyngeal, Cn 9.
46
What is Killian's dehiscence?
The weakest part of the pharyngeal wall. Located inferiorly in the midline. It is the commonest site for a pharyngeal diverticulum.
47
What vessels are found in the carotid sheath?
1. Common carotid artery. 2. Vagus nerve. 3. Internal jugular vein.
48
Where is the carotid sinus located?
At the bifurcation of the common carotid artery.
49
Where does the glossopharyngeal nerve exit the cranial cavity?
Through the jugular foramen.
50
What nerve supplies sensory and taste innervation to the posterior 1/3 of the tongue.
The glossopharyngeal nerve.
51
What does elevation of the soft palate do?
It closes the orifice between the nasopharynx and oropharynx. This occurse during swallowing to prevent food refluxing into the nose. It also occurs in phonation.
52
What nerve supplies sensory sensation to the anterior 2/3 of the tongue?
(different than taste)
* The trigeminal nerve, Cn 5.
* Lingual nerve of the mandibular branch
53
What nerve supplies taste sensation to the anterior 2/3 of the tongue?
The facial nerve, Cn 7. (chorda tympani)
54
What are the functions of the larynx?
* phonation
* cough reflex
* protection of the lower respiratory tract
55
Describe the positioning of the larynx?
* in the anterior compartment of the neck
* suspended from hyoid bone
* spanning between C3 and C6
* continuous inferiorly with the trachea
* open superiorly into laryngeal part of the pharynx
56
What lines the anterior and lateral borders of the larynx?
* anteriorly by the infrahyoid muscles
* laterally by the lobes of the thyroid gland
* major blood vessels ascends laterally
57
What is the clinical relevance of its position in relation to the oesophagus?
* posterior to the larynx as the oesophagus
* emergency intubation
* pressure is applied on the cricoid cartilage
* occludes the oesophagus
* preventing regurgitation of gastric contents
* known as cricoid pressure or Sellick's maneuver
58
The internal cavity allowance can be divided into which three sections?
* supraglottis - From the inferior surface of the epiglottis to the false vocal cords (vestibular folds)
* Glottis - contain the vocal cords and 1 cm below them, the opening between the vocal cords is known as the rima glottidis (its size altered by the muscles of phonation)
* Subglottis - From the inferior border of the glottis to the inferior border of the cricoid cartilage
59
Describe the histology of the interior surface of the larynx? what is the exception?
* All lined by pseudo-stratified ciliated columnar epithelium
* the true vocal cords are lined by stratified squamous epithelium
60
Describe the two arterial supplies to the larynx?
* superior laryngeal artery - branch of the superior thyroid artery (derived from the external carotid), Follows internal branch of the superior laryngeal nerve to the larynx
* inferior laryngeal artery - branch of the inferior thyroid artery (derived From the thyrocervical trunk), Follows the recurrent laryngeal nerve to the larynx
61
Describe the venous drainage of the larynx?
* superior Laryngeal vein - drains into the internal jugular vein via the superior thyroid
* inferior laryngeal vein - drains into the left Brachiocephalic vein via the inferior thyroid vein
62
Describe the motor and sensory innovation by the branches of the vagus nerve to the larynx?
* recurrent laryngeal nerve - sensory innovation to the infraglottis, motor innovation to all the internal muscles of the larynx (except the cricothyroid)
* Superior laryngeal nerve - internal branch provide sensory innovation to the supraglottis, external branch provides motor innovation to the cricothyroid muscle
63
What is the difference between Extrinsic ligaments and intrinsic ligaments in terms of their functions?
* Extrinsic ligaments attached the larynx to external structures
* intrinsic ligaments are responsible for holding the cartilage of the larynx together
64
Name and describe the attachment of the extrinsic ligaments?
* thyro-hyoid membrane - Spines between the superior aspect of the thyroid cartilage and the hyoid bone, pierced laterally by the superior laryngeal vessels and internal laryngeal nerve
* medial thyroid hyoid ligament - anteriomedial thickening of membrane
* Lateral thyrohyoid ligament - posteriolateral thickening of the membrane
* Hyo-Epiglottic ligament - Connects the hyoid bone to the anterior aspect of the epiglottis
* cricotracheal ligament - Connects the cricoid cartilage to the trachea
* Medial cricothyroid ligament - Anteriomedial thickening of the cricoid thyroid ligament, connects the thyroid and cricoid cartilage
65
Name and describe the attachments of the intrinsic ligaments?
* cricothyroid ligament - From the cricoid cartilage and extends superiorly terminating with a free upper margin ( forms the vocal ligament), attached anteriorly to the thyroid cartilage and posteriorly to the arytenoid cartilage
* Quadrangular membrane - spans between the anteriolateral arytenoid cartilage and the lateral aspects of the epiglottis, has free upper margin and lower margin, lower margin is thickened to become the vestibular ligament
66
What is the clinical relevance of the cricothyroid ligament?
* Cricothyroidotomy
* Temporary airway when there is an obstruction at or above the larynx
* palpate the thyroid cartilage make a small incision at the midline of the depression
* insert an endotracheal tube to secure the airway
67
What happens to the vocal folds to control phonation?
abduction, adduction, relaxed and tensed
68
Describe the histology of the vocal fold?
* non-keratinised stratified squamous epithelium
* Reinke's space - amorphous layer rich in glycosaminoglycans, vibrates freely to create sound
* Vocal ligaments - lies at the free upper edge of the cricothyroid ligament
* vocalis muscle - exceptionally fine muscle fibres that lie laterally to the vocal ligaments
* spaces between the vocal cords is known as rima glottidis
69
Describe the positioning of the vestibular folds in relation to the true vocal cords?
* the vestibular folds lie superior in each of the true vocal cords
70
What does the vestibular forwards consist of? What is their function?
* Consist of the vestibular ligament - lower free edge of the quadrangular membrane
* covered by mucous membrane, pink in colour
* provide protection to the larynx
71
How do the functions of the external and internal muscles of the larynx differ?
* the external muscles act to elevate or depress the larynx during swallowing
* the internal muscles act to move the individual components of the larynx - playing a vital role in breathing and phonation
* Change the shape of the rima glottidis, and the length and tension of the vocal cords
72
Name the three groups of the extrinsic muscles?
* superhyoid
* infrahyoid - Attached are the hyoid bone, Depresses the larynx
* stylopharyngeus (pharynx) - Elevates the larynx
73
What innovates all intrinsic muscles of the larynx what is the exception?
* Inferior laryngeal nerve ( terminal branch of the recurrent laryngeal nerve( branch of the vagus nerve itself))
* cricothyroid is innovated by the external branch of the superior laryngeal nerve (derived from the vagus nerve)
74
Describe the cricothyroid muscle? attachment? actions?
* Originates from the anterior aspect of the cricoid cartilage
* attaches to the inferior margin and inferior horn of the thyroid cartilage
* Stretches and tenses the vocal cords
75
Describe the thyroarytenoid muscle? attachment? actions?
* Originates from the inferior posterior aspect of the angle of the thyroid cartilage
* attaches to the anterior lateral part of the arytenoid cartilage
* relaxes the vocal cords allowing for a softer voice
76
Describe the posterior cricoarytenoid muscle? attachment? actions?
* Sole abductors of the vocal folds, only muscle capable of widening the rima glottidis
* Originates from the posterior surface of the cricoid cartilage
* attaches to the muscular process of the arytenoid cartilage
77
Describe the lateral cricoarytenoid muscle? attachment? actions?
* major adductor of vocal folds, narrowing the rima glottidis - modulating the tone and volume speech
* originates from the arch of the cricoid cartilage
* attaches to the muscular process of the arytenoid cartilage
78
Describe the transverse and oblique arytenoid muscles?
* adduct the arytenoid cartilages, closing posterior portion of rima glottidis, Narrowing the laryngeal inlet
* Spans from one arytenoid cartilage to another
79
What marks the laryngeal inlet?
* aryepiglottic folds
* posterior is the hypopharynx (sometimes called laryngo-pharynx)
80
What is the clinical relevance of the piriform fossa?
* Slit like gap lateral to the superior and inferior horns of the thyroid cartilage
* Malignant tumours may be silent as it can grow in the fossa before symptoms develop
81
What nerve supplies the muscles of the tongue?
the hypoglossal nerve (CN XII)
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