Pharynx and Larynx Flashcards
What is the pharynx?
Muscular tube lined with mucosa that communicates with nasal, oral and laryngeal cavities.
Where does the pharynx extend from?
From cranial base to lower border of cricoid cartilage and becomes continues with oesophagus.
What is the cricoid cartilage?
Cartilage that surrounds the trachea near the middle of the neck (below the thyroid cartilage).
Describe the borders of the nasopharynx
Floor formed by soft palate.
Posterior wall - superior constrictor muscle.
Lateral wall - contains opening of Eustachian tube / auditory tube. Lymphoid tissue is behind this.
Roof contains pharyngeal tonsils (lymphoid tissue).
Describe the borders of the oropharynx
Lies beneath soft palate. Can be separated from nasopharynx by raising soft palate (swallowing).
Anteriorly - palatoglossus and palatopharyngeal arches with palatine tonsils between.
Contains the superior constrictor muscle.
What is the blood supply for the palatine tonsils?
Ascending pharyngeal, lingual and lesser palatine arteries
Why is there a risk of haemorrhage during tonsillectomy?
The ascending pharyngeal, lingual and lesser palatine arteries anastomose in the tonsil.
Describe the laryngopharynx
Between superior border of epiglottis and ends at inferior border of cricoid cartilage at C6 by joining into oesophagus.
Contains middle and inferior constrictor muscles.
What are the 4 layers of the pharynx?
- Mucosal coat
- Submucosa
- Muscular coat
- Areolar coat
What does the submucosa contain and why?
Fibrous coat that anchors the pharynx to the cranial base.
What does the areolar coat contain and why?
Buccopharyngeal fascia which covered the exterior of the pharynx.
How do the 3 constrictor muscles work?
They contract sequentially from superior to inferior to constrict the lumen to produce peristaltic waves to move bolus down oesophagus.
What are the 2 longitudinal muscles?
Palatopharyngeus and Stylopharyngeus.
What is the origin and insertion of the Palatopharyngeus?
Arises from palatal aponeurosis and Eustachian tube.
Inserts into posterior part of pharynx, hyoid bone and thyroid cartilage.
What is the origin and insertion of the Stylopharyngeus?
Arises from styloid process.
Descends through gap between middle and inferior constrictor muscles.
Enters pharynx where its fibres mingle with Palatopharyngeus muscle and inserts similarly.
What is the origin of the constrictor muscles?
- Superior = pterygomandibular ligament, alveolar process of mandible and medial pterygoid plate and pterygoid hamulus of the sphenoid bone.
- Middle = stylohyoid ligament and the greater/lesser horns of the hyoid bone.
- Inferior = superior part arises from thyroid cartilage and inferior component arises from cricoid cartilage
Where do the constrictor muscles insert?
They meet at the pharyngeal raphe which attaches to the pharyngeal tubercle on the cranial base (on occipital bone).
What motor nerve innervates the constrictor muscles?
Vagus (X) - pharyngeal branch.
What motor nerve innervates the longitudinal muscles?
Vagus (X) - pharyngeal branch, for all except stylopharyngess which is inverted by Glossopharyngeal (IX).
What are the sensory innervations for the Pharynx?
Main sensory = Glossopharyngeal (IX).
Maxillary branch of Trigeminal (CN V2) - soft palate and roof of pharynx (superior and anterior aspect of nasopharynx).
Inferior laryngopharynx - Vagus (X) - internal branch.
Describe the arterial blood supply of the pharynx.
Via branches of external carotid artery:
- Ascending pharyngeal artery
- Superior & Inferior thyroid artery (pharyngeal branch).
- Facial artery.
- Maxillary artery.
- Lingual artery.
Describe the venous drainage of the pharynx.
Pharyngeal venous plexus, which drains into the internal jugular vein.
Communicates with pterygoid plexus.
Describe the lymphatic drainage of the pharynx.
Most lymph vessels enter the deep cervical lymph nodes.
Some posterior lymph vessels enter the retropharyngeal nodes (lie between the prevertebral and buccopharyngeal fascia).
What bone does the Eustachian tube attach to?
Temporal
Where does the pharyngeal tonsil sit?
Roof and posterior wall of nasopharynx.
What conditions can cause food to travel into the Eustachian tube?
- Vomiting
- Cleft palate
What is the blood supply to the palatine tonsil?
Tonsilar branch of facial artery.
What forms the superior border of the laryngeal inlet?
Epiglottis and laterally by aryepiglottic fold
What is the piriform recess?
Gutter that separates the aryepiglottic fold from the thyroid cartilage and thyrohyoid membrane.
Foreign bodies can lodge in it and removal can damage the internal laryngeal nerve.
Where does the larynx sit?
Anterior to larygopharynx.
Extends from base of tongue to trachea (C3-C6).
Inlet lies behind posterior 1/3 of tongue.
What is the function of the larynx?
- Passageway for air - linking pharynx with trachea.
- Sphincter, preventing food entering trachea.
- Organ of phonation.
What are the 3 unpaired cartilages of the larynx?
- Thyroid
- Cricoid
- Epiglottis
What are the 3 paired cartilages of the larynx?
- Arytenoid
- Cuneiform
- Corniculate
Describe the thyroid cartilage
- Largest.
- 2 quadrilateral plates of hyaline cartilage fused in the midline.
- Posterior parts extend superiorly and inferiorly to form superior / inferior horns. Inferior horns articulate with cricoid cartilage.
Why is the Adam’s apple more prominent in men?
Union between the thyroid cartilage produces a more acute angle in males. This is less prominent in females.
Describe the cricoid cartilage
- Signet-ring shaped.
- Only cartilage to completely encircle the larynx.
- Immediately below thyroid cartilage at level of C6.
- Thin band of quadrilateral plate facing posteriorly.
Describe the epiglottis
- Fibroelastic.
- Leaf-like shape.
- Orientated upwards and backwards lying behind hyoid bone, reaching posterior part of tongue.
Describe the arytenoid cartilage
- 2 pyramid shaped cartilages on posterior lamina of cricoid cartilage.
- Provides attachment for vocal process and has laryngeal muscle insertions.
What type of joint articulates the arytenoid cartilage with the cricoid cartilage?
Synovial joint.
How do the arytenoid cartilages allow phonation?
Laryngeal muscles move the arytenoid cartilages to change length, tension and position of vocal ligaments and folds.
Where are the cuneiform cartilage found?
Aryepiglottic folds (lateral walls of pharynx).
Describe the corniculate cartilage
Tiny elastic cartilages found at apices of arytenoid cartilages
Where are the vestibular folds and vocal folds located?
Vestibular folds = inferior to epiglottis.
Vocal folds = inferior to vestibular folds. Attaches between thyroid and arytenoid cartilages.
What is the space between the vestibular folds and vocal folds called?
Laryngeal ventricle
What are the purpose of the glands in the laryngeal ventricle?
Keep it lubricated to allow speech and resonance.
What is the rima glottidis?
Opening (horizontal fissure) between the true vocal cords and arytenoid cartilage.
What are the ligaments of the larynx?
- Thyrohyoid membrane
- Vocal ligaments
- Ventricular ligaments
- Aryepiglottic ligaments
- Quadrangular membrane
- Cricothyroid membrane
Describe the Thyrohyoid membrane
Fibroelastic sheet joining the inferior surface of the hyoid bone to superior aspect of thyroid cartilage.
Describe the Vocal ligaments
Thick fibroelastic bands that attach between the thyroid and arytenoid cartilages.
Covered by mucous membrane (true vocal folds).
Describe the Ventricular ligaments
2 fibrous bands that run from arytenoid cartilages to internal lamina of thyroid cartilage.
Covered by mucous membrane (false vocal folds = ventricular folds).
These are above the vocal ligaments.
Describe the Aryepiglottic ligaments
Pass upwards from apices of arytenoid cartilage to lateral border of epiglottis.
Describe the Quadrangular membrane
Thin fibroelastic sheet between aryepiglottic ligament and ventricular ligament.
Describe the Cricothyroid membrane
Fibroelastic sheet between vocal folds and cricoid cartilage (conus elasticus).
What are the extrinsic muscles of the larynx?
Supra and infra hyoid muscles.
What are the purpose of the extrinsic larynx muscles?
Move larynx up and down.
What are the intrinsic larynx muscles?
- Posterior cricoarytenoid
- Lateral cricoarytenoid
- Transverse cricoarytenoid
- Vocalis
- Cricothyroid
What are the functions of the intrinsic larynx muscles?
- Open rima to allow air in and out.
- Close rima glottidis and vestibule during swallowing to prevent aspiration of food.
- Control tension in vocal folds for phonation.
What is the function of the vocalis?
Changes tone.
What is the function of the cricoarytenoid?
Stretches vocal folds.
Where do the extrinsic larynx muscles insert into?
Larynx / hyoid bone.
Where do the intrinsic larynx muscles originate from and insert into?
Laryngeal cartilages
What is the function of the Posterior cricoarytenoid?
Open the vocal folds.
What is the function of the Lateral cricoarytenoid?
Close rima glottidis.
Adduct (close) the vocal folds
What is the function of the Transverse cricoarytenoid?
Adduct (close) the vocal folds
What type of joint unites the cricoid and arytenoid cartilages? What movements are possible here?
Synovial joint.
Allows arytenoids to glide on cricoid so they can move closer/further apart.
Arytenoid can also rotate around their vertical axis.
What cartilages form the boundaries of the vestibule?
Anteriorly - epiglottis.
Posteriorly - arytenoid cartilages.
Where is the vestibule located?
Above the vestibular folds.
What does each vocal fold consist of?
Conus elasticus, vocal ligament + muscle fibres which are covered by mucous membrane.
What does the shape of the rima glottidis depend on?
Shape varies according to the movements of the arytenoid cartilages on the cricoid cartilage and the movements between the cricoid and thyroid cartilage.
Which muscle raises the pitch of the voice? How is this achieved?
Cricothyroid.
Elongating and tightening the vocal folds. The lamina of the cartilage is tilted backwards to achieve this.
How dos the internal laryngeal nerve enter the larynx?
Pierces the thyrohyoid membrane.
What is the course of the recurrent laryngeal nerve on the left side? How does it differ to the right?
Left:
- Recurs around arch of aorta and travels between the oesophagus and trachea to reach the larynx.
- Enters the larynx by passing deep to the inferior constrictor muscle.
Right:
- Recurs around the right subclavian artery.
What is the motor innervation to the intrinsic larynx muscles?
Branches of the vagus nerve (CN X).
All muscles supplied by recurrent laryngeal nerve (inferior branch) branch EXCEPT for cricothyroid.
Cricothyroid supplies by superior laryngeal nerve (external branch).
What is the sensory innervation to the intrinsic larynx muscles?
Branches of the vagus nerve (CN X).
Superior laryngeal nerve (internal branch) = mucous membrane ABOVE vocal folds.
Recurrent laryngeal nerve = mucous membrane BELOW vocal folds.
What is the blood supply to the larynx?
Superior thyroid artery - gives off internal laryngeal branch.
Inferior thyroid artery - gives off inferior laryngeal branch.
(accompanies the recurrent laryngeal nerve into larynx).
Laryngeal veins - drains into superior and inferior thyroid veins.
Describe the lymphatic drainage of the larynx.
Above vocal folds: - pierces thyrohyoid membrane to drain into upper deep cervical lymph nodes.
Below vocal folds: - drains into lower deep cervical lymph nodes.
When does phonation normally take place?
During expiration.
What is the average breathing rate?
15 breaths per minute.
How is breathing rate altered when speaking?
Inspiration quicker and expiration slower.
What is the frequency of the flow of air during phonation?
What determines the frequency?
16-20,000 Hz
Frequency determined by sub-glottal pressure and mass/tension on vocal ligaments.
How does phonation occur?
- Vocal cords closed (adducted).
- Air flow obstructed.
- Pressure builds up until it forces folds apart.
- Air escapes.
- Cycle is repeated and converts air into a series of puffs.
What determines the pitch (intonation) and expression?
Frequency of the air.
How are vowels formed?
Via continuous flow of air through the oral cavity.
Shape is modified by tongue and lips.
How are consonants formed?
Via contraction of the vocal tract.
Labial - contact between lips (B, M, P).
Labiodentals - contact between lower lips and incisors (F, V).
Lingopalatal:
- Tip of tongue and anterior part of hard palate (D, T, R).
- Dorsum of tongue and posterior part of hard palate (J, L).
- Dorsum of tongue and soft palate (K).
How are sibilants formed?
Air passes through narrow space between tip of tongue and hard palate (S, SH, Z).
Air expelled through nose (M, N).
What dental problems/issues affect speech?
- Loss of teeth.
- Dentures
(most people adapt). - Cleft palate
- Short lingual frenulum
(these can make speech impossible to understand)
