Lecture 16 and (17?): Pharynx and Larynx Flashcards
What are the 3 divisions of the pharynx ?
Where are they found?
The pharynx is formed by skeletal muscles and fascia.
- This musculofascial half-cylinder extends from the base of the skull to upper border of oesophagus (C6 vertebral level).
- It can be divided into three regions:
- Nasopharynx (behind nasal cavities),
- Oropharynx (behind oral cavity);
- Laryngopharynx (behind superior part of larynx).
The highest point of the pharynx is…
At the base of the skull
Describe the Pharyngeal wall
The pharyngeal wall is attached to bone and cartilage and to ligament superiorly and anteriorly.
The two sides meet posteriorly in the midline at the pharyngeal raphe.
The muscles of the pharynx are organised into two groups based on the direction of their fibres relative to the pharyngeal wall: constrictors (circular) and longitudinal (vertical).
What are the names of the constrictor muscles?
Describe the anatomy of these muscles
There are three constrictor muscles: superior, middle and inferior.
-
Anatomy:
- They are C-shaped muscle with anterior opening and posterior closing.
- The two sides meet posteriorly in the middle at the pharyngeal raphe
- They overlap each other in a fashion resembling the walls of three flowerpots stacked one on the other.
- The gaps between the muscles are reinforced by fascia and provide routes for strucrures to pass through the wall.
- (the bottom is open and so is the anterior side of the superior constrictor muscle)
Describe the function and innervation of the CONSTRICTOR muscles
Function: contract sequentially from top to bottom thus peristalsis of food bolus through pharynx and into esophagus.
Innervation: vagus nerve (CN X)
A special band of muscle (palatopharyngeal sphincter) originates from anterolateral surface of soft palate and circles inner aspect of pharyngeal wall, therefore belongs to inner aspect of superior constrictor.
A special band of muscle (palatopharyngeal sphincter) originates from __________and circles ___________, therefore belongs to __________________\_
A special band of muscle (palatopharyngeal sphincter) originates from anterolateral surface of soft palate and circles inner aspect of pharyngeal wall, therefore belongs to inner aspect of superior constrictor.
Name and Describe the Anatomy of the Longitudinal muscles
Longitudinal muscles include 1) salpingopharyngeus, 2) palatopharyngeus and 3) stylopharyngeus.
-
Anatomy:
- From their sites of origin (base of skull), they run downward and attach into pharyngeal wall.
- (Help stabilise the constrictor muscles)
- From their sites of origin (base of skull), they run downward and attach into pharyngeal wall.
Label
1) Superior constrictor
2) Middle constrictor
3) Inferior constrictor
Label
1) Salpingopharyngeus
2) Palatopharyngeus
3) Stylopharyngeus
(Longitudinal muscles)
Label
1) Pharyngeal tonsil
2) Opening of pharyngotypmaic tube
3) Palaoglossal arch
4) Palatine tonsil
5) Palatopharyngeal arch
Describe the Function and Innervation of Longitudinal muscles
- Function: elevate wall and/or assist swallowing; pull up and over food bolus and push it through pharynx to esophagus.
- Innervation: vagus nerve (CN X), except stylopharyngeus by glossopharyngeal nerve (CN IX).
Where (name the bones) does the superior constrictor attach to the skull?
1) Sphenoid
2) Petrous part of Temporal bone
3) Pharyngotympanic tube
4) Pharyngeal tubercle (occipital)
Where does the Superior Constrictor Mucle attach anteriorly?
Pterygomadibular raphe
Where does the Middle Constrictor Muscle attach anteriorly?
Stylohyoid ligament
Lesser and greater horn of the Hyoid
Where does the Inferior Constrictor Muscle attach ?
Oblique line (where the strap muscles also attach)
Why do the constrictor muscles have such small attachments?
There are lots of structures running between these
Where do the constrictor muscles of the pharynx attach?
Superior Constrictor
- Posterior attachment
- Pharyngeal raphe
- Anterior attachment
- Pteryomandibular raphe
- Adjacent bone on the manidble
- Pterygoid hamulus
Middle constrictor
- Posterior attachment
- Pharyngeal raphe
- Anterior attachment
- Upper margin of greater horn on hyoid bone
- Adjacent margins of lesser horn
- Stylohyoid ligament
Inferior constrictor
- Posterior attachment
- Pharyngeal raphe
- Anterior attachment
- Oblique line of thyroid cartilage
- Cricoid cartilage
Describe the Facia in the neck
Which one in particular is important to the pharynx?
1) Buccopharyngeal
2) Pharyngobasilar Fasica = fascia that runs deep to the mucosa- runs between the mucosa and the constrictor muscle- so trying to stabilise the constrictor muscles.
(below= what?)
Deep fascia of the neck divides into
- Superficial (investing)
- Middle (pretrachel)
- Deep (prevetebral) = Buccopharyngeal Fascia
What structures help stabilise the constrictor muscles?
1) longitudinal muscles
2) Pharyngobasilar fasica
What does the gap above the superior constrictor divide?
Buccinator and Superior Constrictor
What goes through the gaps next to the constrictor muscles?
Structures Passing Through Gaps (Exam: Oropharyngeal Triangle)
Gaps between muscles are reinforced by fascia and provide routes for structures to pass through wall. Understanding their attachment is important.
Above superior constrictor:
- Tensor veli palatini muscle (DNTK)
- Levator veli palatini muscle (DNTK)
Between superior and middle constrictors, and posterior border of mylohyoid (oropharyngeal triangle):
- stylopharyngeus muscle,
- glossopharyngeal nerve (CN IX)
- lingual nerve and vessels.
Between middle and inferior constrictors:
- Internal laryngeal nerve (branch of superior laryngeal nerve) and vessels
Below the inferior:
- Recurrent laryngeal nerve
- inferior laryngeal vessels
If you see folds in the oral cavity there is always……..
A Muscle running underneath the mucosa
What is the clinical implication of adenoid tonsils?
Adenoid tonsil = Pharyngeal tonsil
It fills the whole nasopharynx.
It blocks the nasal cavity from the back. Also the opening for the eustachian tubeopens here.
The adenoid tonsil can get big and block this area
This can cause middle ear infections, cannot breathe through the nose, make noise when breathing etc.
Name the different tonsils
1) Pharyngeal/adenoid tonsil
* Covers the nasopharynx and can block the pharyngotympanic/eustachian tube.
2) Palatine tonsil
* Sits between oral pharynx and oral cavity
When we put the angiotube in. where does it go?
- Through the nose
- Into the Nasopharynx
- Down to the oestrophagus
- Runs through the pharynx
What are palatine tonsils?
The tonsils (palatine tonsils) are a pair of _soft tissue masse_s located at the rear of the throat (pharynx).
Each tonsil is composed of tissue similar to lymph nodes, covered by pink mucosa (like on the adjacent mouthlining). Running through the mucosa of each tonsil are p_its, called crypts._
Diagnose
Clinical: Adenoids
Adenoids are enlarged pharyngeal tonsil (lymphoid tissue) at base of skull / roof of pharynx
Describe the boundaries of the different boarders of the pharynx
-
Nasopharynx:
- behind posterior apertures (choanae) of nasal cavities,
- above soft palate
-
Oropharynx:
- posterior to oral cavity,
- inferior to soft palate,
- superior to upper margin of epiglottis
-
Laryngopharynx:
- extends from superior margin of epiglottis,
- to top of esophagus at level of vertebra C6
Describe the blood supply to the pharynx
Upper part: branches of external carotid artery (lingual, maxillary, facial, ascending pharyngeal artery)
Lower part: branches of _subclavian artery (i_nferior thyroid artery of thyrocervical trunk).
Note: Palatine tonsil supplied by tonsillar branch of facial artery.
Describe the venous drainge and lymphatics of the pharynx
Venous Drainage
- Superior: drain into pterygoid plexus of infratemporal fossa (to facial & superficial temporal, then to internal jugular)
- Inferior: drain into facial and internal jugular vein.
Lymphatic Drainage (Zone 2-5, No Zone 1)
- Lymphatic vessels drain into deep cervical lymph nodes (paratracheal, infrahyoid and retropharyngeal nodes)
- Note: palatine tonsils drain into jugulodigastric nodes.
Describe the Innervation of the Pharyngeal muscles
Innervation
Motor and sensory innervation is mainly by pharyngeal plexus (branches of vagus [CN X] and glossopharyngeal [CN IX]).
- Motor:
- all innervated by vagus nerve (CN X)
- except for stylopharyngeus by glossopharyngeal (CN IX).
-
Sensory:
- laryngopharynx (vagus [CN X])
- oropharynx (glossopharyngeal nerve [CN IX])
- nasopharynx (maxillary nerve [V2])
- Motor:
- all innervated by ______ nerve
- except for _______ by ________ nerve.
-
Sensory:
- laryngopharynx (____ nerve)
- oropharynx (_____ nerve)
- nasopharynx (______nerve)
Innervation
Motor and sensory innervation is mainly by pharyngeal plexus (branches of vagus [CN X] and glossopharyngeal [CN IX]).
- Motor:
- all innervated by vagus nerve (CN X)
- except for stylopharyngeus by glossopharyngeal (CN IX).
- Sensory: ***
- nasopharynx (maxillary nerve [V2])
- oropharynx (glossopharyngeal nerve [CN IX])
- laryngopharynx (vagus [CN X])
What is the epiglottis?
The epiglottis is a flexible flap at the superior end of the larynx in the throat. It acts as a switch between the larynx and the esophagus to permit air to enter the airway to the lungs and food to pass into the gastrointestinal tract.
The larynx is a musculoligamentous structure with a cartilaginous framework located above the___________.
It continues inferiorly with the ________and superiorly opens into _______________..
The larynx is a musculoligamentous structure with a cartilaginous framework located above the lower respiratory tract.
It continues inferiorly with the trachea and superiorly opens into laryngopharynx.
Pharynx had a _____framework, Larynx has a ________ framework
Pharynx had a Skeletal framework, Larynx has a Cartilinagous framework
What cartilages are the larynx formed by?
1) Epiglottis
2) _Thyroid cartilage**_ (thyroid sits below it- not at the thyroid cartilage) ** - has an oblique line (site of attachment of constrictor muscles, deeper muscles of infrahyoid muscles)
3) Cricoid cartilage **(sits below the thyroid cartilage. It is at the C6 level)
- Superior and Inferior horn
- Facet for cricoid (where they join with others)
4) _Arytenoid cartilage *_*(sits above the cricoid cartilage)
5) Cunneiform cartilage (less important- sit in the fascia)
6) Corniculate cartilage (less important- sit in the fascia)
What is another name of ‘adam’s apple’?
Laryngeal prominence
What are the ligaments in the Larynx?
Extrinsic Ligaments
-
Thyrohyoid membrane ** is a tough fibroelastic ligament that spans between thyroid cartilage below and hyoid bone above.
- Posterior borders are thickened to form lateral thyrohyoid ligaments. Triticeal cartilage in each lateral thyrohyoid ligament.
- The anterior midline is thickened to form the median thyrohyoid ligament.
- It has a hole which the internal branch of the sup laryngeal nerve and associated artery runs.
- Hyo-epiglottic ligament extends from epiglottis midline anterosuperiorly to hyoid bone.
- Cricotracheal ligament runs from cricoid cartilage to the first tracheal cartilage, important for tracheostomy.
Intrinsic Ligaments
-
Fibroelastic membrane (intrinsic ligaments) links together laryngeal cartilages and completes laryngeal cavity. It is composed of two parts.
-
1) Cricothyroid ligament (lower) is attached to cricoid cartilage inferiorly, and thyroid cartilage superiorly.
- Superiorly, thickened to form vocal ligament (more medial), which is under vocal fold (true vocal cord).
- Anteriorly, midline thickened to form median cricothyroid ligament, which can be perforated via cricothyroidotomy to establish emergency airway.
-
2) Quadrangular membrane (upper) runs between lateral epiglottis and anterolateral arytenoid cartilage
- Inferiorly is thickened to form vestibular ligament (more lateral), which is under vestibular fold (false vocal cord)
-
1) Cricothyroid ligament (lower) is attached to cricoid cartilage inferiorly, and thyroid cartilage superiorly.
There is an important hole of n extrinsic ligament
1) Name the ligament
2) What goes through this?
Thyrohyoid membrane
The whole is an aperture for internal branch of superior laryngeal nerve and associated artery.
What ligmanet makes up the “true vocal cord”?
Thickening of the upper part of the Cricothyroid ligament
Label from 1-8
1) Thyroid cartilage
2) Epiglottis cartilage
3) Arytenoid cartilage
4) Cricoid cartilage
5) Vestibular ligament
6) Quadrangular membrane
7) Cricothyroid membrane
8) Vocal ligament
Label 9-11
9) Cricothyroid
10) Transverse arytenoid
11) Posterior crico-arytenoid
What is the true and what is the false vocal cord? **
When the artyenoid cartilage moves, it shuts and opens both the false and true vocal cords
The F_alse/vestibular ligamen_t sits more lateral to the true vocal cord (because thte true one is the one we use when we’re breathing- abduct to talk)
When you intubate your patient, do not damage the vocal cords- go between the 2 vocal cords
True:
- Thickening of the superior part of the cricothyroid ligament (Vocal Ligament)
- Runs between the a_rytenoid cartilage_ and the anterior part of the thyroid cartilage
False
-Inferiorly is thickened part of Quadrangular membrane to form vestibular ligament (more lateral), which is under vestibular fold (false vocal cord)
(Vestibular ligament)
- Runs between the epiglottis and the t_hyroid carilage_ and the upper part of the arytenoid cartilage
- Thickening is between the a_nterior part of the thyroid carilage_ to the arytenoid cartilage
Describe the movement of the larynx cartilages
Cricothyroid joints enable t_hyroid cartilage_ to move forward and tilt downward on cricoid cartilage (lengthens and puts tension on vocal ligaments)
Crico-arytenoid joints enable a_rytenoid cartilages_ to r_otate (by pivoting)_, slide away/toward each other (abduct and adduct the vocal ligaments)
Label
1) Cricoid cartilage
2) Arytenoid cartilage
3) Thyroid cartilage
4) Glottis
5) Vocal cord
6) Superior horn of thyroid cartilage
Label
1) Vocal cord
2) Vestibular fold (false vocal cord)
3) Ary-epiglottic fold
Describe the divisions of the larynx
The larynx is divided into three areas by pairs of mucosal folds, the vestibular and vocal folds.
These divisions are
(1) vestibule;
(2) middle part (very thin and between folds);
(3) infraglottic space.
Label 1-8
1) Tongue
2) Epiglottis
3) Ary-epiglottic fold
4) Cuneiform tubercle
5) Corniculate tubercle
6) Vestibular fold
7) Vocal fold (true vocal cord)
8) Rima glottidis (opening between vocal cords)
Label 9-12
9) Laryngeal inlet
10) Vestibule
11) Piriform recess
12) Laryngopharynx (closed)
If someone has a fish bone stuck in their throat, where is it likely to be?
Piriform recess- on the lateral to the ary-epiglottic fold
The piriform recess lies on either side of the laryngeal inlet. It is bounded medially by the aryepiglottic fold and laterally by thyroid cartilage.
It is a common place for food or foreign bodies to become trapped (e.g. a fish bone).
What is the piriform recess?
The piriform recess lies on either side of the l_aryngeal inlet_. It is bounded medially by the aryepiglottic fold and laterally by thyroid cartilage.
It is a common place for food or foreign bodies to become trapped (e.g. a fish bone).
Why do we have it? - Piriform recess makes up most of larynx in babies. When they’re lying down and drinking milk, this helps them drink milk fast. Larynx is small, so the PR is larger (comparatively) so milk can go fastly into the oesophagus.
What muscle opens the airways?
Posterior Crico-arytenoid
MUST KNOW - keeps us alive
What is the name of the sapce between the two vocal cords?
Rima glottidis is the space between two adjacent true vocal cords (true vocal cords produce sounds when they are adducted and air is forced between them).
Rima vestibuli is the space between two adjacent vestibular folds (false vocal cords).
What happens when we’re swallowing?
Epiglottis shuts the door of the larynx. Epiglottis swings downwards to cover glottis (narrow laryngeal inlet) and open esophagus.
Babies cannot use the epiglottis because it comes up to the nasopharynx (too high)
Describe the blood supply of the laryngeal muscles
What is the clinical significance of this?
Blood Supply
-
Superior laryngeal artery from superior thyroid (originating from external carotid artery)
- Above the vocal cords
-
Inferior laryngeal artery from inferior thyroid (originating from subclavian artery)
- Below the vocal cords
When you are removing the thyroid, you have to make sure you ligate the Superior Thyroid right at the thyroid gland. If you ligate the Superior thyroid artery at the origin, it cannot supply the larynx.
Describe the Venous and Lymphatic drainage of the larynx
Venous Drainage
- Superior laryngeal veins drain into superior thyroid veins, which in turn drain into internal jugular vein.
- Inferior laryngeal veins drain into inferior thyroid veins, which in turn drain into left brachiocephalic vein.
Lymphatic Drainage
- Above vocal folds: drain into deep cervical nodes associated with bifurcation of common carotid artery
- Below vocal folds: drain into deep nodes (paratracheal) associated with upper trachea.
Describe the Innervation of the Larynx
Sensory and motor innervation of larynx is by two branches of vagus nerve, which are 1) recurrent laryngeal nerves and 2) superior laryngeal nerves.
- Recurrent laryngeal nerve supplies motor to all intrinsic muscles (except cricothyroid) and sensory below vocal folds.
-
Superior laryngeal nerve divides into internal and external laryngeal nerve:
- External laryngeal nerve: motor to cricothyroid muscle;
- Internal laryngeal nerve: mainly sensory above vocal folds.
Recurrent laryngeal nerve supplies _________________
Superior laryngeal nerve divides into ________________ and supplies ______________________
Recurrent laryngeal nerve supplies motor to a_ll intrinsic muscles_ (except cricothyroid- not important) and sensory b_elow vocal folds._
Superior laryngeal nerve divides into internal and external laryngeal nerve:
- External laryngeal nerve: motor to c_ricothyroid muscle;_
- I_nternal laryngeal nerve:_ mainly sensory above vocal folds.
Label
1) Right common carotid artery
2) Right vagus nerve
3) Right recurrent laryngeal nerve
4) Right subclavian artery
5) Left common cartoid artery
6) Left vagus nerve
7) Thyroid Gland
8) Left recurrent larygen nerve
9) Left subclavian artery
10) Larynx
What is a cricothyroidotomy and tracheostomy?
Tracheostomy is performed to relieve airway obstruction or protect the airways and can be emergent or planned.
Cricothyroidotomy is a safer alternative in an emergency situation. These procedures may be technically _challenging due to patient facto_rs (e.g. obese patients or those with a short neck).
Describe Tracehostomy
What could be damaged in this procedure?
The patient is suitably prepared and positioned. Palpable midline structures are used as reference points. These points are (from inferior to superior): suprasternal notch, cricoid cartilage and superior thyroid notch.
- A horizontal incision (in relation to midline) is made midway between suprasternal notch and cricoid cartilage.
- Skin, platysma and superficial veins (communicating veins between anterior jugular vein) are divided together with investing layer of deep fascia of neck.
- Strap muscles are retracted laterally to expose thyroid isthmus. Pretracheal fascia encloses thyroid isthmus, which usually overlies second and third tracheal ring. Thyroid isthmus with its fascia are divided and overseen before incising second and third tracheal rings. First tracheal ring must be avoided!
It is important to stick to the midline in order to avoid injuring 1) recurrent nerves, 2) carotid sheath and 3) inferior thyroid veins. In an emergency, a vertical midline incision may be used rather than a transverse cervical incision.
What are the divisions of the larynx?
The larynx is divided into three areas by
pairs of mucosal folds, the vestibular and
vocal folds. These divisions are:
1) Vestibule.
2) Middle part (very thin and between folds).
3) Infraglottic space.
