The Pharynx

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The Pharynx
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The Pharynx

• Passageway to the respiratory and digestive
  tracts
• Air / nourishment pass via pharynx en route to
  respective passages
• Length approx 12.5 cm
• Location between
• Nasal, oral, and laryngeal cavities anteriorly
  and cervical vertebrae C1 C6 posteriorly

http//www.nsknet.or.jp/katoh/image/pharynx.gif
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Functions Composition of Pharynx

• Composition
• Muscles lined with mucous membrane
• Mucous memb of pharynx continuous with that of
  Nasal, oral, and laryngeal cavities

• Functions
• Respiratory passage
• Digestive passage
• Role in phonation
• Yields different vowel sounds

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The Pharynx is not a Closed Tube

• It is open anteriorly to nasal, oral, and
  laryngeal cavities

Choanae
nasopharynx
oropharynx
Laryngopharynx (hypopharynx)
esophagus
Netter, Frank H., Atlas of Human Anatomy.
Ciba-Geigy Corporation, Summit, N.J. 1993. Plate
60.
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The Pharyngeal Tubercle

• Located on cranial base anterior to foramen
  magnum
• On occipital bone
• The Pharyngeal Raphe descends from the pharyngeal
  tubercle

• The Pharynx
• Runs through C6
• Located anterior to bodies of cervical vertebrae
  C1-C6

http//biology.clc.uc.edu/fankhauser/Labs/Anatomy_
_Physiology/AP201/Skeletal/skull_from_belowPB012
152up.JPG
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Muscles of the Pharynx

• Pharyngeal wall is different from most of the
  alimentary (digestive) system.
• There is an external layer of intrinsic circular
  muscles and an internal layer of extrinsic
  longitudinal muscles.

Internal Longitudinal
External Circular
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Muscles of the Pharynx

• Internal Group
• Palatopharyngeus
• Stylopharyngeus
• Salpingopharyngeus

• External Group
• Superior constrictor
• Middle constrictor
• Inferior constrictor

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The External Group of Pharyngeal Muscles
These muscles constrict the pharynx during
swallowing They contract sequentially from
superior to inferior pushing the bolus into the
esophagus All 3 constrictors are innervated by
CN X via the pharyngeal plexus (SVE)
Stacked like styrofoam cups Superior Constrictor
innermost Inferior Constrictor - outermost
sensory fibers to pharynx are from IX and V2
(GVA)
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The Pharyngeal Raphe

• Descends from the pharyngeal tubercle
• Serves as the continuous attachment of the
  external group of pharyngeal muscles.

http//www.yorku.ca/earmstro/journey/images/pharyn
x.jpeg
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Superior Constrictor

• O Pterygomandibular raphe (connects to
  posterior aspect of buccinator m. ) This raphe is
  attached to the pterygoid hamulus and the area
  distal to the third molar known as the retromolar
  triangle.
• I Pharyngeal raphe

http//content.answers.com/main/content/wp/en-comm
ons/thumb/2/27/230px-Gray1031.png
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Middle Constrictor

• O Stylohyoid ligament greater lesser horns
  of hyoid
• I- Pharyngeal raphe

http//content.answers.com/main/content/wp/en-comm
ons/thumb/4/40/250px-Gray1030.png
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Inferior Constrictor

• O - Cartilages of larynx (continuous origin from
  oblique line of thyroid cartilage through lateral
  aspect of cricoid)
• Inferior fibers sometimes called cricopharyngeus
• I Pharyngeal raphe
• Unique Action inferior fibers blend with
  esophagus prevent air from entering esophagus,
  these fibers relax during swallowing

http//content.answers.com/main/content/wp/en-comm
ons/thumb/4/40/250px-Gray1030.png
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• There are gaps between the constrictors through
  which structures enter/exit the pharynx
• The Pharyngobasilar Fascia Superior to the
  superior constrictor closes gap between superior
  constrictor and base of skull

Netter, Frank H., Atlas of Human Anatomy.
Ciba-Geigy Corporation, Summit, N.J. 1993. Plate
61.
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Internal (Longitudinal) Muscles

• Palatopharyngeus
• Stylopharyngeus
• Salpingopharyngeus

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Palatopharyngeus
O - Palatine aponeurosis I Lateral muscular
wall of pharynx posterior aspect of thyroid
cartilage A - Elevates pharynx and larynx to
close the oropharyngeal isthmus during swallowing
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Internal (Longitudinal) Muscles Stylopharyngeus

• Stylopharyngeus
• O med surface of styloid process
• Passes to pharynx between sup. middle
  constrictors
• I Thyroid cartilage (continuous with
  palatopharyngeus)
• N CN IX
• A elevates pharynx larynx
• Can expand pharyngeal wall over large bolus
  during swallowing

Stylo-pharyngeus
Netter, Frank H., Atlas of Human Anatomy.
Ciba-Geigy Corporation, Summit, N.J. 1993. Plate
61.
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Salpingopharyngeus

• O Cartilaginous part of auditory tube
• I Descends inside constrictors blends with
  palatopharyngeus
• N Pharyngeal plexus (X)
• A -Elevates pharynx and larynx during swallowing
• Opens auditory tube during swallowing
• In lab note salpingopharyngeal fold

Salpingopharyngeus
Netter, Frank H., Atlas of Human Anatomy.
Ciba-Geigy Corporation, Summit, N.J. 1993. Plate
61.
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The Interior of the Pharynx

• The pharynx communicates with 3 cavities
• Nasal cavity
• Via nasopharynx
• Oral cavity
• Via oropharynx
• Laryngeal cavity
• Via laryngopharynx

http//www.55a.net/firas/photo/45118pharynx.jpg
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Nasopharynx

• Respiratory function
• Posterior to nasal cavity
• Between choanae soft palate
• Contains
• Pharyngeal tonsil (adenoids)
• Auditory Tube

http//www.hpb.gov.sg/data/hpb.home/media/images/h
az/nasopharynx.jpg
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Oropharynx

• Posterior to soft palate
• Level C2 C3 (to hyoid bone)

http//www.stanford.edu/class/humbio103/ParaSites2
004/Lagochilascaris/oropharynx.jpg
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The Laryngopharynx
C4 C6 Hyoid Bone Esophagus Communicates with
larynx at laryngeal inlet
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Deglutition (Swallowing)

• 3 Stages
• In mouth
• In pharynx
• In esophagus

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Stage 1 In Mouth

• Voluntary
• Chewing breaks food down into increasingly
  smaller size
• Tongue, lips and cheeks maneuver food in oral
  cavity until bolus is formed
• Bolus pushed into oropharynx by tongue

http//greenfield.fortunecity.com/rattler/46/image
s/Eat3.gif
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Stage II in Pharynx (Involuntary)

• The pharyngeal stage of deglutiton is stimulated
  when the bolus enters the oropharynx. This stage
  of swallowing is mainly due to a reflex response.
  Various nerve receptors send messages to the
  deglutition centre of the brain stem.

http//greenfield.fortunecity.com/rattler/46/image
s/Eat4.gif
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Stage II

• Pharyngeal walls contract. (Constrictors
  contract successively). The soft palate is
  elevated and closes off the nasopharynx. The
  hyoid bone is pulled superiorly which raises the
  larynx. This closes the larynx off to the passage
  of food. This is extremely important in
  preventing food from entering the airway.
• Breathing and chewing stop

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Stage III

• Bolus is pushed (squeezed) from the
  laryngopharynx to the esophagus by the inferior
  constrictor. From the esophagus food continues
  to the stomach as digestion continues.

http//greenfield.fortunecity.com/rattler/46/image
s/Eat5.gif
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The Larynx
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Functions of the Larynx

• Protective sphincter at inlet to airway
• Voice production
• Part of respiratory pathway

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Location of the Larynx

• Opposite C3 C6
• Anterior to laryngopharynx
• Superiorly opens to laryngopharynx
• Inferiorly continuous with trachea

http//www.origin8.nl/medical/images2/larynx.jpg
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Larynx

• Consists of cartilages attached by
• Ligaments
• Membranes
• The cartilages are moved by muscles

• The Cartilages
• Cricoid
• Thyroid
• Arytenoid x2
• Epiglottis

http//www.throat-cancer-symptoms.com/assets/image
s/imgTCShome-larynx.jpg
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The Cricoid Cartilage

• Complete ring of hyaline cartilage
• Looks like signet ring
• Narrow anterior arch
• Broad posterior lamina
• Lateral surface facets for articulation of
  thyroid cartilage
• Superolateral surface facret for articulation
  of arytenoid cartilage

All of the articulations between the cartilages
are synovial!
http//anatomy.uams.edu/anatomyhtml/graphics/rsa3p
6.gif
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The cricoid cartilage is stationary It is the
base on which the other cartilages move
http//sprojects.mmi.mcgill.ca/larynx/notes/anat/i
mages/cricoid.gif
http//www.ling.yale.edu16080/ling120/Larynx/Lary
nx_side.gif
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The Thyroid Cartilage

• Largest cartilage
• Superior margin opposite C4 vertebra
• 2 plates (laminae) of hyaline cartilage
• Plates joined at Adams apple (the laryngeal
  prominence)
• Open posteriorly
• Oblique line attachment of
• sternothyroid
• thyrohyoid
• inferior constrictor

Superior Horn
Oblique Line
Inferior Horn
http//www.yorku.ca/earmstro/journey/images/thyroi
d.gif
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Cricothyroid Joint
Inferior horns of thyroid cartilage articulate
with lateral surface of cricoid cartilage.
Main movements at this joint are rotation and
gliding which alter vocal fold length.
Netter, Frank H., Atlas of Human Anatomy.
Ciba-Geigy Corporation, Summit, N.J. 1993. Plate
71.
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The Arytenoid Cartilages

• Paired
• Pyramidal in shape
• On posterior wall of larynx
• Sits on superolateral surface of cricoid
• Each cartilage has a
• Base
• Apex
• Muscular process
• Projects posterolaterally
• Vocal process
• Projects anteriorly

Netter, Frank H., Atlas of Human Anatomy.
Ciba-Geigy Corporation, Summit, N.J. 1993. Plate
71.
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The Cricoarytenoid Joint
Between arytenoid bases superolateral surface
of cricoid lamina

• Enable arytenoids to
• Slide toward one another
• Tilt anteriorly and posteriorly
• Rotate
• These motions approximate and separate vocal folds

Netter, Frank H., Atlas of Human Anatomy.
Ciba-Geigy Corporation, Summit, N.J. 1993. Plate
71.
37
Epiglottic Cartilage

• Shaped like a tennis racket
• Elastic (not hyaline) cartilage
• Protrudes from behind root of tongue and hyoid
  body
• Attached to superior margin hyoid bone
  (hyoepiglottic lig.).
• Stem runs to thyroid angle (thyroepiglottic lig.)

http//www.gpc.edu/jaliff/larynx.gif
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Membranes of the Larynx

• Thyrohyoid membrane
• Cricotracheal ligament
• Quadrangular ligament
• Crocothyroid ligament conus elasticus

Extrinsic - attached to structures outside of
larynx
Intrinsic
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Extrinsic Laryngeal Membranes

• Thyrohyoid Membrane
• Connects superior border of thyroid cartilage and
  its superior horn with hyoid bone
• Cricotracheal Ligament
• Unites lower border of cricoid and first tracheal
  cartilage

Cricotracheal Lig.
The hyoid bone is not considered part of the
larynx, although membranes and muscles attach the
two
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Intrinsic Laryngeal Membranes

• The fibroelastic membrane of the larynx
• Lies deep to mucous membrane of the larynx
• A broad sheet of fibrous tissue containing many
  elastic fibers
• On either side it is interrupted by the
  vestibular and vocal folds

Vestibular fold
Vocal fold
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Schematic Illustration of Larynx J.Basmajian
b vocal process c muscular process (receives
muscle insertions_
a vocal lig.
C cartilage/ cricoid M membrane (conus
elasticus)
Hyoid bone
Aryepiglottic fold
d superior and inferior horns of thyroid
cartilage (thyroid is mid-sagittally sectioned)
Q quadrangular membrane v vestibular ligament
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• From the vestibular fold superiorly, the membrane
  is called the quadrangular membrane
• From the vocal fold inferiorly, the membrane is
  called the cricothyroid lig. or conus elasticus.

Quadrangular membrane
Cricothyroid membrane
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The Quadrangular Membrane

• Extends between
• Arytenoid cartilage
• Epiglottic cartilage
• Its free superior margin is the superior margin
  of the larynx and aryepiglottic lig. (fold).
• Its inferior margin is called the vestibular
  ligament. With its mucosa it is called the
  vestibular fold (false vocal folds).
• Tiny cartilages lie within the aryepiglottic
  folds.

Quadrangular membrane
Vestibular fold
Ariepiglottic fold
http//www.bartelby.net/107/Images/small/image953.
jpg
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Cricothyroid Ligament(Conus Elasticus)

• On anterosuperior aspect of cricoid rim and along
  free margin of cricoid through slope of posterior
  cricoid lamina and vocal process of arytenoid
  cartilages
• Anteriorly attaches to posterior aspect of
  thyroid prominence

vestibular
Cricothyroid Lig.
http//www.bartelby.net/107/Images/small/image953.
jpg
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The True Vocal Cords

• The thickened free superior margins of the
  cricothyroid ligament form the vocal ligament,
  the skeleton of the true vocal cords.

Uvula
Tongue
Hyoid Bone
Epiglottis

• The true vocal cords are
• Mucus membrane
• A muscle (the vocalis)
• The superior margin of the membrane the vocal
  lig.

Vestibule of Larynx
False Vocal Fold
True Vocal Fold
Trachea
http//facstaff.bloomu.edu/jhranitz/Courses/APHNT/
Lab_Pictures/layngopharynx_sagw.jpg
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The Rima Glottidis

• The Rima Glottidis -
• The gap between the vocal folds (posteriorly
  between the vocal processes)
• (The rima vestibuli is the gap between the false
  vocal folds.)

Netter, Frank H., Atlas of Human Anatomy.
Ciba-Geigy Corporation, Summit, N.J. 1993. Plate
73.
47
Muscles of the larynx

• Extrinsics
• Elevators
• Swallowing
• Depressors
• After swallowing

• Intrinsics
• Control laryngeal inlet
• Move vocal folds

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Extrinsic Muscles of the Larynx

• Elevators of larynx during swallowing (to close
  off laryngeal inlet)
• Suprahyoids
• Thyrohyoid m.
• Extrinsic (internal) pharyngeal muscles
• Stylopharyngeus
• Salpingopharyngeus
• Palatopharyngeus

• Depressors of the Hyoid
• 3 infrahyoids
• Sternohyoid
• Sternothyroid
• Omohyoid
• Thyrohyoid

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Intrinsic Muscles of the Larynx

• Cricothyroid
• Thyroaryteniod Vocalis
• Posterior Cricoarytenoid
• Lateral Cricoarytenoid
• Transverse Arytenoid
• Oblique Arytenoid

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Cricothyroid m.
O side of cricoid cartilage I inferior margin
and inferior horn thyroid lamina N external
laryngeal branch of superior laryngeal branch of
X A tenses and elongates vocal ligament
Netter, Frank H., Atlas of Human Anatomy.
Ciba-Geigy Corporation, Summit, N.J. 1993. Plate
72.
51
Tensing and Relaxing the Vocal Cords
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Thyroarytenoid (vocalis) m.
O post surface thyroid cartilage I Muscular
process arytenoid cart. N recurrent branch of
X A relaxes vocal folds by approximating
thyroid to cricoid
Cricoid Cart.
Arytenoid Cart.
The most medial fibers next to the vocal ligament
called the vocalis muscle
Thyroarytenoid M.
Vocal Lig.
Vocalis M.
Netter, Frank H., Atlas of Human Anatomy.
Ciba-Geigy Corporation, Summit, N.J. 1993. Plate
72.
53
Posterior Cricoarytenoid

• O posterior aspect of cricoid
• I muscular process arytenoid cart.
• N recurrent branch of CN X
• A abducts vocal folds

Netter, Frank H., Atlas of Human Anatomy.
Ciba-Geigy Corporation, Summit, N.J. 1993. Plate
72.
54
Lateral Cricoarytenoid
O Lateral aspect of cricoid I Muscular
process of arytenoids N Recurrent branch X A
Adducts vocal folds
Netter, Frank H., Atlas of Human Anatomy.
Ciba-Geigy Corporation, Summit, N.J. 1993. Plate
72.
55
Transverse Arytenoid
Netter, Frank H., Atlas of Human Anatomy.
Ciba-Geigy Corporation, Summit, N.J. 1993. Plate
73.
http//www.meddean.luc.edu/lumen/meded/grossAnatom
y/dissector/mml/images/tary.jpg
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Oblique Arytenoid
Also pulls epiglottis towards arytenoids to close
laryngeal inlet. A few fibers continue into
aryepiglottic folds to help in this process.
http//www.meddean.luc.edu/Lumen/Meded/Grossanatom
y/dissector/mml/images/oary.jpg
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Note

• Motor
• Cricothyroid is innervted by the external
  laryngeal branch of superior laryngeal branch of
  X (SVE).
• All other intrinsic muscles of the larynx are
  innervated by the recurrent laryngeal branch of
  X(SVE).
• General Sensory
• General sensory innervation to the larynx from
  vocal folds superiorly from internal laryngeal
  nerve (X) (GVA).
• General sensory innervation to the larynx
  inferior to vocal folds from recurrent laryngeal
  nerve (X) (GVA).

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Innervation
X
Superior Laryngeal branch of X
Internal Laryngeal branch (pierces thyrohyoid
membrane with sup. Laryngeal br. of sup. thyroid
a.)
External Laryngeal branch To cricothyroid m.
Recurrent Laryngeal branch of X
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Blood Supply

• Laryngeal arteries - branches of superior and
  inferior thyroid arteries
• Veins follow arteries
• Superior laryngeal v ultimately drains into IJV
• Inferior laryngeal v generally drains into Left
  Brachiocephalic V.

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Larynx 2 functions

• 1. protection sphincter
• 2. voice production
• 2 sphincters
• 1. inlet
• 2. rima glottidis
• Inlet used only during swallowing

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Swallowing

• As food passes from tongue to pharynx
• Larynx is elevated
• Laryngeal inlet narrowed by
• Oblique arytenoid
• Transverse arytenoid
• Lateral cricoarytenoid
• Tongue pushes epiglottis back to cover the inlet

The tongue pushes the epiglottis posteriorly to
cover the inlet