Transcript lecture 9 - Fredonia.edu

Laryngeal Anatomy
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Phonation
• Generation of a voiced sound
• Accomplished with the larynx (voice
box)
• Voiceless sounds: open vocal folds
• Voiced sounds: closed vocal folds
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Vocal Folds
• 5 layers of tissue (deep= muscle)
• Glottis= space between the vocal folds
• Subglottal= area below the vocal folds
• Located at the end of the airstream at
superior end of trachea
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Structural Support of the Larynx
• Larynx is suspended in the neck by a
single bone, the hyoid bone.
• There are 6 laryngeal cartilage's:
– 3 paired
– 3 unpaired
– provide structural support for the larynx.
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Laryngeal Cartilage's
• Epiglottis:
-shaped like a long leaf,
-base attached to inner portion of anterior
rim of the thyroid cartilage,
-folds down over airway to protect during
swallowing.
-composed of elastic cartilage (does not
ossify with age...must remain flexible).
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Laryngeal Cartilage's
• Thyroid Cartilage:
-angled saddle-shaped curve,
-anterior attachment of true vocal folds,
-posteriorly there are 2 superior cornu and 2
inferior cornu (articulate with cricoid
cartilage),
-composed of hyaline cartilage- does ossify
& limit flexibility with age,
-lateral walls are laminae attach to midline
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of notch.
Laryngeal Cartilage's
• Cricoid :
-signet
ring shaped,
-2 sets of paired faces to allow
connection (articulation) with other
joints,
-cricothyroid joint connects the cricoid
to the inferior cornu of the thyroid
cartilage.
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Laryngeal Cartilage's
• Arytenoids:
– Pair of small cartilages shaped like
pyramids
– Mounted opposite each other on the rim of
the signet portion of the cricoid cartilage
– 2 motions:
• rotation
• gliding
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Laryngeal Cartilage's
• Corniculate & Cuneiform Cartilage's:
– Corniculate: attached to superior tips of the
arytenoid cartilage
– Cuneiform: embedded in the muscular complex
superior to the corniculate
– Provide no clear function; may add to the
stability to the abduction movement.
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Laryngeal Cartilage's
• 3 Unpaired
Cartilage's
-Epiglottis
-Thyroid
-Cricoid
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• 3 Paired
Cartilage's
-Cuneiform
-Corniculate
-Arytenoid
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Larynx & Trachea
Hyoid Bone
Thyroid Cartilage
Cricoid Cartilage
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Laryngeal Cartilages
Thyroid
Thyroid
Notch
Vocal Ligament
Superior horn
Cricoid
Inferior horn
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Arytenoid Movement
• Rock= Front sides tilt toward or away from each
other
• Glide= Their back sides slide toward or away from
each other
• Abduction= open vocal folds (caused by rocking &
gliding)
• Adduction= closed vocal folds
• Arytenoids have 2 processes:
– Vocal process (vocal folds attach)
– Muscular process (muscle attachment)
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Arytenoid Movement
Rocking
Gliding
Adducted
Abducted
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Laryngeal Membranes & Ligaments
• Extrinsic Laryngeal Membranes:
• Connect the laryngeal cartilages with
adjacent structures
– Hyothyroid membrane
– Paired lateral hyothyroid ligaments
– Hyoepiglottic ligament
– Cricotracheal membrane
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Hyothyroid Membrane & Ligaments
• Occupies space between the hyoid bone and
superior border of the thyroid cartilage
• Membrane is thickened medially= Middle
Hyothyroid Ligament
• Posteriorly between the superior thyroid
horns the membrane is thickened= Lateral
Hyothyroid Ligament
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Hyoepiglottic Ligament
• Unpaired, midline, elastic ligament
extending from anterior surface of the
epiglottis to the upper border of the
hyoid bone
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Cricotracheal Membrane
• Connects the lower border of the cricoid
cartilage with the upper border of the
first tracheal ring
• More extensive then membrane
attaching tracheal rings
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Laryngeal Membranes & Ligaments
• Intrinsic Laryngeal Membranes:
• Interconnects the various laryngeal cartilages
and helps regulate the extent & direction of
their movement
– Conus Elasticus
– Quadrangle membrane
– Aryepiglottic folds
– Lateral cricothyroid membrane
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Conus Elasticus
• Cavity below the vocal folds is funnel or coneshaped
• Continuous sheet of membrane that connects the
thyroid, cricoid and arytenoid cartilages with one
another
• Divided into a medial cricothyroid ligament and
two lateral cricothyroid membranes
• Extends from superior border of the arch and
lamina of the cricoid cartilage to the upper limits
of the true vocal folds
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Quadrangular Membranes
• Arise from the lateral margins of the
epiglottis and adjacent thyroid cartilage
near the angle
• Fibers coarse posteriorly downward and
attach to the corniculate cartilage's
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Aryepiglottic Folds
• Superior margins of the quadrangular
membranes
• Cuneiform cartilages embedded here
• Implicated in the mechanics of
swallowing
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Lateral Hyothyroid
Ligament
Hyothyroid
Membrane
Conus Elasticus
Membranes & Ligaments
Arytenoid
Cartilage
Epiglottis
Middle Hyothyroid
Ligament
Throid Lamina
Cricotracheal
Membrane
Hyoepiglottic
Ligament
Vocal ligament
Conus Elasticus 24
Conus Elasticus
T= Thyroid
A= Arytenoid
C
A
CE
T
C= Cricoid
CE= Conus Elasticus
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Quadrangular Membrane
Heavy Lines=
Aryepiglottic
Folds & Quadrangualr
Membrane
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Reading/Assignments
• Seikel: Pgs. 164-182
• Maue-Dickson: Pgs. 139-160
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