17 the pharynx e learning

8/2/2019 17 the Pharynx e Learning

1/27

The Pharynx


2/27

Pharynx

The pharynx is 3 times larger than the larynx

A funnel shaped fibromuscular tube extends from the base of

skull & continues below with esophagus at the level of C6

Divided into 3 parts:

Nasal: nasopharynxbehind the nasal cavity

Oral: oropharynx

Behind the oral cavity

Laryngeal: laryngeopharynxbehind the larynx


3/27

Walls of Pharynx

Ant. :deficient

communicates with the nose,the mouth and the larynx

Lat. & Post. Walls:

1. mucous memb.

2. fibrous covering

3. Muscles


4/27

Muscles of Pharynx

(Read your text for origin, insertion, innervation & action of these muscles)

6 Muscles

3 constrictors:

Sup., mid. & inf.

- Run in circular direction & attached post. to pharyngeal raphe

- The successive contraction of these muscles produces theaction of swallowing

Overlap each other in the direction of inferior to superior( the inferior constrictor is covering the lower part of the middleconstrictor and the middle constrictor is covering the lowerpart of the superior constrictor )


5/27

Additional slide

- The superior constrictor originate from the medial pterygiod plate andpterygomandibular raphe ( a ligament extending from the medialpterygoid plate the pterygoid hamulus all the way down to the

posterior end of mylohyoid line on the mandible )

- The pterygomandibular ligament is a very important ligament in thedental clinical practice ( the origin of the superior constrictor muscle) also providing an attachment for the buccinator muscle, becauseits the landmark to give the inferior dental block anaesthesia ( to

anaesthesize the inferior alveolar nerve before it enters themandible through the mandibular foramen ) , you have to but the

needle lateral to the pterygomandibular raphe and medial to theramus of the mandible ( you penetrate the buccinator muscle ), theneedle can be inserted even to 2.5 cm because its a gap area

- The pterygomandibular ligament providing attacments ( anteriorly tothe buccinator muscle and posteriorly to the superior constrictor

muscle)


6/27

Additional slide

- The borders of the infratemporal fossa are the ramus of themandible and the lateral pterygoid plate

- In the infratemporal fossa the mandibular nerve will divide :

- the most anterior branch lingual nerve

- in the middle the inferior alveolar nerve- the posterior one the auriculotemporal nerve

- Those are the three sensory branches of the posterior division of themandibular nerve

- You actually anaesthesize the ( inferior alveolar and the lingual

nerves) , thats why when you give ID block always youll ask thepatient if he has parasthaesia on the side of the tongue, this is anindication that the anaesthesia is working

- You have to insert your finger to touch the ramus of the mandible andtense the mucosa ( to be very easy to find the pterygomandibular

raphe )


7/27

Additional slide

- The middle constrictor arises from the stylohyoid ligament and partof the greater horn of the hyoid bone

- The inferior constrictor ( the largest one ) arises from the oblique lineof thyroid cartilage and from the cricoid cartilage

- 3 muscles are attaching to the oblique line those are : sternothyroid,thyrohyoid, and the inferior constrictor

- The upper part of the inferior constrictor muscle ( which arises fromthe oblique line ) , we refer to it as thyropharyngeus muscle and its

helping in the action of swallowing

- The lower part of the inferior constrictor which is more horizontallygoing and arising from cricoid cartilage, we refer to it ascricopharyngeus

- The cricopharyngeus fibers once they contract they act as asphincter, closing the pharynx and preventing the food from

regurgitation


8/27


9/27

Killians Dehiscence

Dehiscence = gapInferior constrictor m. consists of

2 parts:

- Sup.: thyropharyngeus

- Inf.: cricopharyngeus

* A weak area presents between

The 2 parts of inf. constrictor m.

The clinical significance of Killiansdehiscence :

m.m. may protrude giving riseto a pharyngeal pouchsometimes, the very smoothfood can stuck there producing

uncomfortable sensation anddifficulty in swallowing ( dysphagia )


10/27

3. Stylopharyngeus m.:

styloid process post. Border ofthyroid cartilage

pass between superior and middleconstrictor muscles

Innervation : pharyngeal plexus

4. Palatopharyngeus m.:

Palatal apon. post. Border ofthyroid cartilage Palatopharyngeal fold

5. Salpingopharyngeus m.:

Auditory tube (medial end)

Blends with palatopharyngeus

- Once it contracts it helps in the openinng of the pharyngealorrifice for the Eustachian tube so the air can pass to themiddle ear to balance the pressure on both sides of the

tympanic membrane

*All of these muscles help elevate the

pharynx

Salpingo = tube


11/27

- All the muscles of the pharynx are innervated by thepharyngeal plexus except (the stylopharyngeus muscle - by

the glossopharyngeal nerve)

- The pharyngeal plexus is a network of nerves formed by the cranialnerves IX, X and XI ( glossopharyngeal, vagus and accessorynerves ) on the wall of the pharynx

- The motor innervation to all muscles of the pharynx is from thepharyngeal plexus

( mainly from the vagus nerve )- Sensory supply - mainly glossopharyngeal

- In the gag reflex, when we work on the posterior teeth or when youtry to place a denture, the patient tries to vomit once you touch theposterior part ( the oropharynx ) or the soft palate ( the roof of the

oropharynx ), this touching will induce irritation this irritation willinduce sensory signals in the glossopharyngeal nerve, from therethis signal will go to the vagus nerve which will induce contraction inthe constrictor muscles through the pharyngeal plexus, but thiscontraction will be opposite ( the inferior then the middle then the

superior ) so they will push upwards rather than backwards


12/27


13/27

Nasopharynx

Post. To nasal cavity & above the

soft palateLined by respiratory epithelium

Contains:

- auditory tube:

opens into the middle ear

On the lateral walls of thenasopharynx

- Tubal tonsil:

aggregation of lymph nodules

around the auditory tube- the microorganism can passthrough the tube into the middleear producing ( otitis media )

- Tubal elevation &Salpingopharyngeal fold

- Pharyngeal tonsil (adenoid):in the submucosa of the

roof of the nasopharynx


14/27

Oropharynx

Post. To oral cavity & opens to it

Through oropharyngeal isthmus

Between the soft palatesuperiorly and the posterior

3

rd

of the tongue inferiorly Atthe level of C2 and C3

The floor is made by:

post. 1/3 of tongue & thevalleculae

Contains:Palatine tonsils:

between palatoglossal andpalatopharyngeal folds

over sup. Constrictor m.

tonsillar bed


15/27

Oropharyngeal isthmus & Valleculae


16/27

Relations of Palatine Tonsils

Ant.: palatoglossal fold

Post.: palatopharyngeal fold

Sup.: soft palate

Inf.: posterior 3rd of thetongue

Medially: the cavity of theoropharynx

Laterally: superior constrictormuscle


17/27

Tonsillitis & Tonsillectomy

Tonsillitis: inflammation of the tonsils (palatine)Acute (causes virus : EBR, influenza virus, herpes simplix virus-

the tonsils are swollen and reddish lasts for a short period oftime fever, sore throat & dysphagia) Vs. Chronic (causebacterial ( hemolytic streptococcus group A in the thorax

causes endocarditis) treatment : antibiotics ( most common :amoxycillin if the patient is allergic to penicillin he is givenerythromycin) with pain relief )

- Acute : 6 days , chronic : can last for 3 weeks

Tonsillectomy: removal of palatine tonsils

* Some argue that tonsilectomy is unnecessary surgery & may bedangerous because:

you remove one source of immunity

Others argue that chronically inflamed tonsils are a site ofrecurrent infection.

Inflammation of pharyngeal tonsil adenoiditis


18/27

Laryngeopharynx

From epiglottis to cricoid C.

At vertebral level C4,C5 & C6

Lined by stratified squamousepithelium

Contains:

- Piriform fossa( Piriform = pear shaped )

- A small depression or recesson each side of the laryngealinlet


19/27

Piriform Fossa

A small recess (depression) on

Each side of laryngeal inlet

Bounded:

Med.: qudrangular membrane

Lat.: thyroid cartilage

Fxn. : prevent swallowing of sharpand foreign objects

* Internal laryngeal n. pass

In the fossa just beneath the m.m.


20/27

Innervation of The Pharynx

Sensory:

Naso: maxillary nerve (V2)

Oro: glossopharyngeal

Laryngeo: vagus

Motor:

Pharyngeal plexus

to all muscles of pharynx Exceptstylopharyngeus


21/27

Gag Reflex

Involved both sensory & motor innervations of pharynx workingtogether

Sensory stimulation of pharyngeal mucosa

(via IX)

Contraction of pharyngeal musculature

(from XI via X to pharyngeal plexus)


22/27


23/27


24/27

Pharyngeal Gaps

4 gaps

Above sup. Constrictor m.:

Eustachian tube, ascending palatineartery ( branch from the facialatrery ), tensor velli palatinemuscle, levator velli palatinemuscle

Between sup. & mid. Constrictor m.:

stylopharyngeus muscle,glossopharyngeal nerve

Between mid & inf. Constrictors:superior laryngeal artery, internal

laryngeal nerveBelow inf. Constrictor:

inferior laryngeal artery,recurrent laryngeal nerve

- Those gaps allow for structures topass inside and outside of the

pharynx


25/27

Above Sup. Constrictor M.


26/27

Waldeyers Tonsillar Ring

Pharyngeal Tonsil:single, roof of nasopharynx

Tubal Tonsils:

on lat. Walls of nasopharynx

Palatine Tonsils:

on lat. Walls of oropharynx

Lingual Tonsil:single, floor of oropharynx (posterior 3rd ofthe tongue )


27/27

Done by : Muad Al-ZoubiBest wishes

17 the pharynx e learning

Documents