The Pharynx And Larynx Flashcards
What is the pharynx
Muscular tube which lies in the neck
Forms part of respiratory and gastrointestinal systems
Structure of walls of pharynx
Outer layer of circular muscle and inner layer of longitudinal muscle
Pharynx external circular muscle layer
Composed of 3 constrictor muscles- superior, middle and inferior constrictors- that overlap
Contract superior to inferior so that swallowed food moves down pharynx to oesophagus
Process of swallowing
Food in oral cavity pushed into oropharynx by tongue
Soft palate rises and closes off Nasopharynx from oropharynx
Food enters laryngopharynx and constriction of muscles of pharyngeal wall move food into oesophagus
Epiglottis closes off laryngeal inlet and prevents food/liquid entering larynx
3 parts of pharynx and locations
Nasopharynx- posterior to nasal cavity
Oropharynx- posterior to oral cavity
Laryngopharynx- posterior to larynx
Tonsils
Collections of lymphoid tissue in upper parts of pharynx
4 types of tonsils
Pharyngeal
Tubal
Palatine
Lingual
Location of pharyngeal tonsil (x1)
Lies in roof of Nasopharynx
Location of tubal tonsils (x2)
Surrounds opening of the auditory tube which connects Nasopharynx to middle ear
Location of palatine tonsils (x2)
Lies next to pharyngeal wall in oropharynx
Location of lingual tonsil (x1)
Collection of lymphoid tissue on posterior aspect of tongue
Sensory Innervation of pharynx
Glossopharyngeal nerve
Motor Innervation of pharynx
Vagus nerve- coordinates contraction of the pharyngeal muscles and soft palate
Which nerves lie close to the posterior pharyngeal wall
Cervical part of sympathetic trunk and superior cervical ganglion
Superior laryngeal nerve (passes between inferior and middle constrictors of the pharynx to the larynx)
Hypoglossal nerve
Glossopharyngeal nerve
Number of laryngeal cartilages
9
3 paired
3 unpaired
3 unpaired laryngeal cartilages
Epiglottis
Thyroid cartilage
Cricoid cartilage
3 paired laryngeal cartilages
Arytenoids
Cuneiforms
Corniculate
Thyroid cartilage of larynx
Composed of 2 flat cartilages (laminae) that meet in anterior midline to form laryngeal prominence
Laminae form extensions that project superiorly and inferiorly- superior and inferior horns
What does the superior horn attach to
Hyoid bone
What do the inferior horns articulate with
Cricoid cartilage below
Cricothyroid membrane
Connects inferior border of thyroid and superior border of cricoid
Membrane is pierced to create an emergency airway
Epiglottis
Attached to superior aspect of thyroid cartilage, where 2 thyroid laminae meet
During swallowing, epiglottis covers entrance to larynx (laryngeal inlet)
Arytenoids
Sit on superior surface of cricoid cartilage- articulate at small joints
Small
Movement of Arytenoids move the vocal cords
2 pairs of folds that project into laryngeal cavity
Vestibular folds (false vocal cords) superiorly
Vocal folds (true vocal cords) inferiorly
Narrow space separates them
Vestibular folds
Folds of mucous membrane that lie superior to vocal folds
Provide protection to larynx
Vocal folds
Folds of mucous membrane that cover and protect the vocal ligaments
Vocal ligaments
Attached anteriorly to internal aspect of laryngeal prominence and posteriorly to Arytenoid cartilages
Laryngeal prominence
Point where 2 thyroid laminae cartilages meet
Rims glottidis
Space between true vocal cords
Adduction of true vocal cords
Closes the rima glottidis
Abduction of the true vocal cords
Opens the rima glottidis
Phonation requires
Adduction of the cords and closure of the rima glottidis
Abduction of the cords opens the rima glottidis when:
To a small degree in Whispering
Partially in normal breathing
Fully in forced breathing
Intrinsic laryngeal muscles
Move the laryngeal cartilages and hence the vocal cords
Left and right cricothyroid muscles
Anteriorly between thyroid and cricoid cartilages
Contraction places tension on vocal chords
Left and right posterior cricoarytenoids
On posterior surface of cricoid
Each attached to the ipsilateral Arytenoid
Abduct the vocal chords and opens the rima glottidis
Transverse Arytenoid
Unpaired muscle on posterior aspect of larynx which connects the 2 Arytenoid cartilages
Muscles adduct the vocal folds and close the rima glottidis
Extrinsic laryngeal muscles
Suprahyoid and infrahyoid muscles
Move larynx as one with speech and swallowing
Superior laryngeal nerve
Innervates cricothyroid muscles and is sensory to larynx above the vocal folds
Branch of vagus nerve
Recurrent laryngeal nerve
Innervates all the intrinsic muscles (except the cricothyroid muscle) and is sensory to larynx below the vocal folds
Branch of vagus nerve
Surface anatomy of neck
• hyoid bone inferior to the mandible
• thyroid cartilage in the midline of the neck (the ‘Adam’s apple’)
• cricoid cartilage in the midline, inferior to the thyroid cartilage
• first tracheal cartilage inferior to the cricoid cartilage
• cricothyroid membrane between the thyroid cartilage and cricoid cartilage – this can be punctured to create an emergency airway
• lobes of the thyroid gland either side of the upper trachea and inferior larynx
• carotid pulse – best palpated just anterior to sternocleidomastoid at the level of the thyroid cartilage.
Waldeyer’s ring
Ringed arrangement of tonsils
Location of pharynx
Begins at base of skull and ends at inferior border of cricoid cartilage (C6)
Nasopharynx
continuous with the nasal cavity and performs a respiratory function by conditioning inspired air and propagating it into the larynx.
This part of the pharynx is lined with respiratory epithelium; ciliated pseudostratified columnar epithelium with goblet cells.
The posterosuperior nasopharynx contains the adenoid tonsils, which enlarge between 3-8 years of age and then regress.
Oropharynx
involved in the voluntary and involuntary phases of swallowing
It contains the following structures:
Posterior one-third of the tongue.
Lingual tonsils – lymphoid tissue at the base of the tongue.
Palatine tonsils – lymphoid tissue located in the tonsillar fossa (between the palatoglossal and palatopharyngeal arches of the oral cavity).
Superior constrictor muscle
Laryngopharynx
continuous inferiorly with the oesophagus.
It is found posterior to the larynx and communicates with it via the laryngeal inlet, lateral to which one can find the piriform fossae.
The laryngopharynx contains the middle and inferior pharyngeal constrictors.
Pharyngeal plexus
Pharyngeal branches from the glossopharyngeal nerve (CN IX).
Pharyngeal branch of the vagus nerve (CN X).
Branches from the external laryngeal nerve.
Sympathetic fibres from the superior cervical ganglion.
Arterial supply to pharynx
branches of the external carotid artery:
Ascending pharyngeal artery
Branches of the facial artery
Branches of the lingual and maxillary arteries.
Venous drainage of pharynx
pharyngeal venous plexus, which drains into the internal jugular vein.
Location of larynx
located in the anterior compartment of the neck, suspended from the hyoid bone, and spanning between C3 and C6.
Arterial supply to larynx
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.
Venous drainage of larynx
superior and inferior laryngeal veins.
The superior laryngeal vein drains to the internal jugular vein via the superior thyroid, whereas the inferior laryngeal vein drains to the left brachiocephalic vein via the inferior thyroid vein.
Reinke’s space
watery, amorphous layer in vocal folds rich in glycosaminoglycans. Due to its fluidity, the epithelium is able to vibrate freely above it to create sound.
Role of hard palate
Helps break down food
separating the oral cavity from the nasal and sinus cavities, thus allowing proper phonation and articulation, as well as breathing and chewing
Soft palate
serves to elevate the nasopharynx, effectively closing the communication from the oropharynx to the nasopharynx. The soft palate is comprised of five muscles that play essential roles in breathing, phonation, and swallowing.
Uvula
(Dangling bit at back of throat attached to soft palate)
secrete saliva to moisten your mouth and throat. But it also aids in eating and drinking
Adenoid tonsils
posterosuperior nasopharynx contains the adenoid tonsils, which enlarge between 3-8 years of age and then regress.
Waldeyer’s ring
ring of lymphoid tissue in the naso- and oropharynx formed by the paired palatine tonsils, the adenoid tonsils and lingual tonsil
Causes of abnormal swallowing
Stroke
Cerebral palsy
Parkinson’s disease
Treatment for difficulty swallowing
Speech and language therapy (SALT)
NG tube
Thickeners to food
Advice to chew food more thoroughly, take smaller bites etc
Cricothyroid membrane
Connects lower border of thyroid cartilage with upper border of cricoid cartilage in midline
Laryngoscope
a thin tube with a light, lens and a video camera that helps providers look closely at your larynx
Vallecula
important reference landmark used during intubation of the trachea.
curved laryngoscope tip is placed in the vallecula, exerting upward and forward force on the hyoepiglottic ligament to elevate the epiglottis
epiglottic vallecula is a depression just behind the root of the tongue between the medial and lateral glosso-epiglottic folds in the throat. These depressions serve as “spit traps”; saliva is temporarily held in the valleculae to prevent initiation of the swallowing reflex.
posterior cricoarytenoid muscles
sole abductors of the vocal folds, and thus the only muscle capable of widening the rima glottidis.
Attachments: Originates from the posterior surface of the cricoid cartilage and attaches to the muscular process of the arytenoid cartilage.
Actions: Abduction of the vocal folds.
Innervation: Inferior laryngeal nerve (branch of recurrent laryngeal).
lateral cricoarytenoid muscles
major adductors of the vocal folds. They narrow the rima glottidis, modulating the tone and volume of speech.
Attachments: Originates from the arch of the cricoid cartilage and attaches to the muscular process of the arytenoid cartilage.
Actions: Adduction of the vocal folds.
Innervation: Inferior laryngeal nerve (branch of recurrent laryngeal).
transverse and oblique arytenoids muscles
adduct the arytenoid cartilages, closing the posterior portion of rima glottidis. This narrows the laryngeal inlet.
Attachments: Spans from one arytenoid cartilage to the opposite arytenoid.
Actions: Adduction of the arytenoid cartilages.
Innervation: Inferior laryngeal nerve (branch of recurrent laryngeal).
Which muscle abduct the cords and opens the rims glottidis
Posterior cricoarytenoids
Which muscle adducts the vocal chords and closes the Roma glottidis
Transverse arytenoid
Contraction of the cricothyroid results in…
Contraction of cricothyroid lengthens the cords and places tension on them.
Sensory nerve supply to larynx
Internal laryngeal nerve = above vocal cords
Recurrent laryngeal nerve = below vocal cords
Motor nerve supply to the lungs
Superior laryngeal nerve = cricothyroid muscle
Recurrent laryngeal nerve - all other muscles
What are the recurrent and superior laryngeal nerves branches from
Vagus nerve
What is the internal laryngeal nerve a branch from
Superior laryngeal nerve
Angle of laryngeal prominence in men
90 degrees
Angle of laryngeal prominence in women
120 degrees
Which nerve supplies the cricothyroid muscle
External branch of superior laryngeal nerve
