Pharynx: Fri, Oct 6

Front 1

Pharynx: Intro

Back 1

*12-15 cm tube
*begins at base of skull adn extends to junction with esophagus (inferior border of cricoid cartilage
*5cm wide superiorly
*1.5cm wide inferiorly-narrowed part of GI tract
*mixture of air and food in upper part of pharynx

Front 2

Walls of Pharynx:

Back 2

1. mucosa
2. submucosa: (pharyngobasilar fascia); deep to tonsil
3. muscular layer: inner longitudinal and outer circular
4. palatine tonsil: lies in mucosa
5. buccopharyngeal fascial layer-posterior to pharyngeal muscles
6. retropharyngeal space-posterior to buccopharygeal fascia

Front 3

Subdivisions of Pharynx:

Back 3

1. nasopharynx: posterior nasal aperture or choanae is opening from nasal cavity
*extends from base of skull to tip, inferior end of soft palate (uvula)
2. oropharynx: runs from uvula to tip end of epiglottis
3. larygopharynx: from epiglottis to inferior border of cricoid cartilage (C6 vertebrae)

Front 4

Nasopharynx:

Back 4

1. choanae
2. pharyngeal tonsil-on superior aspect of posterior wall
3. ostium (1.5cm from inferior conchal bone) and opening of eustachian tube
4. torus tubarius: swelling produced by medial portion of eustachian tube
5. salpingopharyngeal fold: extends down from torus tubarius into pharynx
6. pharyngeal recess: cleft where cancers form
7. parapharyngeal space: lateral to recess, where infections from teeth can spread
8. pharyngeal isthmus: bridge between naso- adn oro- pharnyx's
9. levator palatini
10. tensor palatini: anterolateral to levator
**CC: both muscles elevate and pull soft palate posteriorly to close off nasopharynx from oropharynx during 2nd stage of deglutition (involuntary)

Front 5

Eustachian tube:

Back 5

**conduit connecting nasdopharynx to middle ear
**purpose to equalize pressure on either side of tympanic membrane
**also conduit for bacteria
**cartilaginous (medial 2/3) and bony (lateral 1/3)portions
**not a complete ring but is completed by membrane

**CC: 1) Valsalva maneuver-equalizes pressure (holding nose and blowing with mouth closed); 2) otitis media (middle ear infection): more common in children b/c eustachian tube is shorter, wider and more horizontal

Front 6

Soft Palate:

Back 6

1. uvula- appendage hanging down to separate naso- and oro- pharynx's
2. made of glands, minor salivary glands
3. five muscles in posterior aspect:
a) tensor palatini
b) levator palatini
c) palatoglossus
d) palatopharyngeus
e) muscularis uvuli: cause rolling "r" in spanish

Front 7

Oropharynx:

Back 7

**bound by soft palate superiorly, base of tongue inferiorly, arches laterally
1. palatoglossus muscle: short and brief, deep to fold and anterior to palatine tonsilar bed
2. pharyngobasilar fascia lies over tonsil bed; used as lateral boundary for tonsilectomies
3. throat, or fauces, lies between palato- glossal and pharyngeal folds
4. superior constrictor muscle: forms bed of tonsil
5. palatoglossal muscle
6. palatopharyngeus muscle
7. epiglottic folds: lie between epiglottis and tongue

Front 8

Innervation and Blood supply:

Back 8

1. paratonsillar (external palatine) vein
**CC: bleeding after tonsilectomy usually from paratonsillar vein

2. tonsillar branch of facial artery (main supply): 5 arteries of tonsillar bed

Nerves:
1. glossopharyngeal: only nerve to tonsillar bed-supplies taste and sensation to posterior 1/3 of tongue; can be found in gap between middle and superior constrictors (as well as stylohyoid lig and stylopharyngeus
2. lingual nerve-may be sacrificed in tonsillectomies

*CC: surgeon can go through thin superior constrictor and nick coiled ICA

Front 9

Laryngopharynx:

Back 9

1. aditus: opening of larynx-marked laterally by aryepiglottic folds
2. bulge for cricoid cartilage and piriform recess, a mucosal fold covering internal laryngeal nerve

Front 10

Muscles of Pharynx:

Back 10

3 Inner Longitudinal:
1. salpingopharyngeus-most superior
2. palatopharyngeus
3. stylopharyngeus-upper fibers external to pharynx
*muscles blend together and attach inferiorly into wall of pharynx and superior-posterior aspects of thyroid cartilage
**contraction of longitudinal muscles widens adn shortens pharynx as it receives bolus of food

Outer Circular Layer:
1. superior constrictor: attaches anteriorly to pterygomandibular raphe and bone at either end-medial pterygoid plate (hamulus) and mandibular part, just posterior to mylohyoid line
2. middle constrictor: arises from stylohyoid lig, lesser horn of hyoid, and superior border of greater horn of hyoid
3. inferior constrictor: arises from thyroid and cricoid cartilages; has 2 portions: oblique thyropharyngeus and horizontal cricopharyngeus
**contract in sequence to force bolus of food down esophagus
*have common posterior attachment: midline raphe

Front 11

Gaps:

Back 11

1. between skull and superior constrictor: pharyngobasilar muscle pierced by auditory tube and levator palatini; ascending palatine br of facial artery an dascending pharyngeal artery pass over gap
2. between superior and middle constrictors: stylohyoid lig, stylopharyngeus, and CNIX
3. between middle and inferior constrictors: thyrohyoid membrane pierced by internal laryngeal nerve and superior laryngeal artery

**CC: in between thyropharyngeus and cricopharyngeus is thinnest layer of GI tract: Killian's Dehiscence-a pharyngeal diverticulum can occur b/c area of least resistance

Front 12

Nerves of Pharynx:

Back 12

1. V2: pharyngeal br of V2 supplies some afferent fibers to upper part of pharynx just superior to ostium of auditory tube
2. CNIX: afferent fibers to area from just superior to ostium to termination of pharynx
3. CNX: internal laryngeal branches supply some of pharynx

A. Pharyngeal plexus:
*lies on posterior aspect of middle constrictor
1. CNX (SVE) fibers are motor to most muscles of pharynx
2. CNIX: sensory to most of pharynx
3. CNIX: motor branch (SVE) supplies stylopharyngeus
4. sympathetics: from pharyngeal branches of sympathetic trunk

*note: internal laryngeal pierces region of piriform recess
*recurrent laryngeal passes between cricopharyngeaus and muscle of esophagus
*recurrent becomes inferior laryngeal where thyroid cartilage junctions with cricoid cartliage

Front 13

Blood Supply:

Back 13

ECA gives off 8 branches:
(SALFOPSM)
1. Superior thyroid
2. Ascending pharyngeal
3. Lingual
4. Facial
5. Occipital (posteriorA)
6. Posterior auricular (posterior)
7. Superficial temporal (terminal)
8. Maxillary (terminal)

**CCA bifurcates at superior level of thyroid cartilage
**termination of ECA into 2 branches is at level of neck of mandible

A. carotid sinus: dilatoin in distal portion of CCA and initial portion of ICA (baroreceptors)
*CC: if pressed, stimulates increase pressure and results bradycardia, resulting in reducing pulse rate and possibly fainting.
*could also break off calcified cholesterol, resulting in stroke

B. carotid body: is a chemoreceptor in bifurcation of CCA

Veins:
1. pharyngeal veins drain into pharyngeal plexus of veins, which typically drains into IJV, BUT can drain into facial of lingual

Front 14

Lymphatics:

Back 14

1. superifial nodes in head and face take shape of collar
2. superficial cervical
3. deep cervical (deep to SCM)
*omohyoid crosses IJV and divides deep cervical into superior and inferior sets
4. pharynx drains to deep cervical (retropharyngeal)
5. palatine tonsil drains into jugulodigastric node (deep cervical)

**superficial lymphatic drainage of head and neck all drain into deep cervical, which in turn drain to jugular trunk.
a. left side: thoracic duct
b. right sidea: right lymph duct

Front 15

Lymphoid tissue:

Back 15

**adenoids: when pharyngeal tonsil is enlarged
**may be collection of lymphoid tissue at opening of eustachian tube. if enlarged due to infection, plugs up nasopharyngeal opening (middle ear infection)
**additional tissue in palatine and lingual tonsils
**Waldeyer's Ring: ring of tissue guarding the orifices of pharynx