The Larynx Medical Clinical Anatomy

The Larynx
Medical Clinical Anatomy
March 26, 2012
Today: The Larynx
●Functions of the Larynx
● Anatomy
-Cartilages
Today in Lab: Thomas Carroll, MD
Director
The Center for Voice and Swallowing
Assistant Professor
Department of Otolaryngology
Tufts Medical Center
-Muscles
-Membranes – quadrangular membrane
conus elasticus
● Laryngeal Papillomas, Nodules, Polyps
● Videos:
-The Vocal Cords in Action
-Laryngeal Papillomas – before and after surgery
-Endotracheal Intubation
● What to do in lab today
Surface Anatomy of the Neck
Mental process
Hyoid bone
Trapezius
Thyroid cartilge
Supraclavicular
fossa
Cricoid cartilage
clavicle
Sternocleidomastoid
muscle.
Jugular
notch
Surface Anatomy of the Neck
Hyoid bone
Thyroid cartilage
Crocoid cartilage
Thyroid gland
Larynx
Cartilages connected by ligaments and moved by
muscles
Functions:
1. Phonation
2. Closes respiratory system – allows increase in
abdominal pressure (Valsalva maneuver)
3. Also acts with oral cavity, oral pharynx in the
process of deglutition (swallowing)
The Larynx
• The larynx is a 5-7 cm
long structure.
• Upper boundary starts at
the tip of the epiglottis,
opposite the 3rd to 4th,
cervical vertebra.
• Lower end is at the lower
border of the cricoid
cartilage.
• Lies opposite the 6th
cervical vertebra.
Superior constrictor
Middle constrictor
Inferior constrictor
Larynx
cricopharyngeus
esophagus
The Larynx: Anatomy
•
The structural rigidity of the larynx is
provided by the three median (unpaired)
cartilages:
– The epiglottis
– Thyroid cartilage
– Cricoid cartilage
– ,
Also 3 paired cartilages:
- Arytenoid
- Corniculate
- Cuneiform
along with the hyoid bone.
•
The thyrohyoid membrane forms a Cshaped barrier around the anterior and
lateral walls of the supraglottis
Opening for
superior
laryngeal artery
and internal
laryngeal nerve
Thyrohyoid
membrane
Superior horn
Thyroid notch
Inferior horn
Cricothyroid
membrane
Hyoepiglottic
ligament
thyroid
Thyroepiglottic
ligament
Oblique
line
arytenoid
Cricothyroid joint
Corniculate
cartilage
Arytenoid cartilage
Muscular process
of arytenoid
cartilage
Lamina of cricoid
cartilage
Vocal process of
arytenoid cartilage
Vocal
ligaments
Arytenoids = penguins
cricoid = seat
lid = epiglottis
Areytenoids can glide and
rotate on the lamina of
the cricoid
These movements can
change the angle
between the vocal
ligaments, thereby
causing them to adduct
and abduct
Rima glottidis
Variations in the shape of the rima glottidis. – varies according to the
position of the vocal folds
Extrinsic Muscles of the Larynx –
Elevate the Larynx during speaking and
swallowing
palatopharyngeus
stylopharyngeus
Digastric, stylohyoid,
mylohyoid – elevate hyoid
bone and larynx
(The Suprahyoid Muscles)
Stylopharyngeus – inserts on superior border
of thyroid cartilage and pharynx
Palatopharyngeus – inserts on posterior
margn of thyroid cartilage and wall of pharynx
Sternothyroid muscle depresses (or elevate – thyrohyoid) larynx
directly
Thyrohyoid m.
Sternothyroid m.
Aryepiglottic
muscle - draws the
epiglottis posteriorly
and downward
during swallowing
rima
glottidis
Vocalis m.
Actions of intrinsic laryngeal
Muscles
Cricothyroid m.
tenses vocal cords
Posterior cricoarytenoid
abducts vocal cords
Lateral
cricoarytenoid
adducts
Transverse
arytenoids
adducts
Thyroarytenoid &
vocalis relaxes
vocal cords
Vocalis relaxes
segments of
vocal lligaments,
thereby adjusting
pitch
Interior View of Larynx
Thyroepiglottic
m.
thyroarytenoid
Lateral
cricoarytenoid
cricothyroid
Thyroepiglottic muscle
- draws the epiglottic
cartilage downward
represents the superior
fibers of thyroarytenoid
muscle which fan out to
the quadrangular
membrane and epiglottis
Nerves of Larynx
+ sup. Laryngeal a.
Supplies cricithyroid
muscle + inferior
constrictor
Supplies all other
muscles of larynx
Superior
laryngeal artery
Internal
laryngeal nerve
external
laryngeal nerve
Posterior View of
Pharynx
Superior, middle,
inferior constrictor
muscles
Internal laryngeal
nerve
palatopharyngeus
stylopharyngeus
Oblique, transverse
interarytenoid m.s
Posterior
cricoarytenoid m.
Internal laryngeal n.
superior laryngeal
artery
Piriform recess
Recurrent laryngeal
nerve
Superior Laryngeal nerve Block
Used to abolish the cough
reflex during laryngoscopy
and bronchoscopy
Recurrent Laryngeal Nerve
Block
Superior Deep cervical
nodes (larynx above
vocal folds)
Inferior Deep cervical
nodes (larynx below
vocal folds)
Membranes of the Larynx
Quadrangular Membrane
→Vestibular Folds
Conus Elasticus
→ True Vocal Folds
Cricothyroid Membrane
Thyrohyoid Membrane
Quadrangular Membrane
Closes off space between
epiglottis and arytenoids
Posterior View of
Pharynx
Aryepiglottic folds
overlie
quadrangular
membrane
Cricoid
cartilage
covered with
mucosa
Piriform recess
esophagus
Aryepilgottic fold
(Upper free edge
of quadrangular
membrane)
Quadrangular
Membrane
Lower free edge of
Quadrangular
membrane is called Vestibular
Ligament; deep to Vestibular
(False Vocal) Folds
saccule
Conus Elasticus Functions
1) Sound Production – Vibrate
like lips of trumpet player;
2) Closed Rima Glottidis stops
outflow air, upward movement
of diaphragm - when contracted
abdominal muscle pressure
increases in abdominal cavity;
occurs in childbirth, defecation
Conus Elasticus –
Vibrating membranes that
arise from the entire upper
edge of cricoid.
Attach to Thyroid cartilage
anteriorly, Arytenoid cartilage
posteriorly
air
Superior free edge =
vocal ligament
Tent can
expand
outward
The conus elasticus – like a pup tent with a slit at the top
Conus elasticus – considered to
be lateral extension of
cricothyroid membrane
Quadrangular membrane
Vestibular ligament
ventricle
Vocal ligament
Conus elasticus
Vallecula fossa
False vocal cord
vestibule
ventricle
True vocal cord
True vocal cords: the mucosal covering of the vocal ligament,
thyroarytenoid and vocalis muscles
Quadrangular
membrane
Conus
elasticus
Laryngocele
Air-filled sac communicating with the ventricle of the
larynx.
Seen in glassblowers, trumpet players, etc. due to
continual forced expiration producing increased
pressures in the larynx which leads to dilatation of the
laryngeal ventricle. It is also seen in people with chronic
obstructive airway disease
The Glottis -The combination of the vocal folds and the space
between them
Laryngeal function: Airway Protection
The glottis: open for inspiration and closed for swallowing
Open
Closed
Mechanics of Swallowing
Soft palate elevated and
tensed
Bolus of food
enters oral cavity
and is pushed
backward into
oropharynx by
tongue
Laryngeal inlet
closed (vocal cords
adducted)
Tongue elevated and
retracted
Epiglottis depressed
Larynx and
pharynx elevated
Upper esophageal
sphincter relaxed,
allowing bolus of
food to enter
esophagus
True vocal cords
False vocal
cords
Rima glottidis
ventricle
The Larynx
Piriform
recess
Superior surface anatomy:
Epiglottis
Vallecula
The Larynx
Superior surface anatomy:
True
Vocal
Cords
Ventricle
False
Vocal
Cords
Anterior
Commissure
Aryepiglottic
Fold
The Larynx
Superior surface
anatomy:
Cartilaginous
Rings of
Trachea
Vocal Cord
Sulcus (on
True Vocal
Cords)
False
Vocal
Cords
Cricoid
Ring
True
Vocal
Cords
http://www.youtube.com/watch?v=iYpDwhpILkQ
YouTube - Beth's First Laryngoscopy - Vocal Cords in Action
Laryngitis
Laryngitis: the swollen pink vocal
cords are almost the same color as
the surrounding tissue
A more normal set of vocal
folds is white and shiny
Laryngeal Papillomas
Papillomas - benign epithelial tumors
that are caused by infection with the
human papilloma virus (HPV).
Symptoms include hoarsness that is
proportional to size of papilloma
Eventually, these tumors may block
the airway passage and cause
difficulty breathing.
May be treated with laser surgery
http://www.youtube.com/watch?v=kRI9AV
heKdQ
Vocal nodules
A nodule differs from a polyp in that it is a
growth of the epithelium that covers the
mucous membrane, not of the mucous
membrane itself. Thus, it has a structural
resemblance a callus on the hand. If one has
vocal cord nodules, the voice will become
breathy and hoarse.
Vocal cord polyps
Polyps are lesions that develop from voice
abuse, chronic laryngeal allergic reactions and
chronic inhalation of irritants, such as industrial
fumes and cigarette smoke.
The Hills are Alive
with…
Other Celebs Who Lost (?) Their Voice to Laryngeal Pathology
http://content.nejm.org/cgi/video/356/17/e15/
Dissection of Larynx
epigolittis
1) Posterior cricoarytenoid m.
2) Transverse arytenoid m.
3) Quadrangular membrane
4) Inferior laryngeal nerve
Piriform
recess
Part II of lab – Disarticulation of
Skull from Vertebral Column
Goal: examine structures in
retropharyngeal space
●Superior cervical ganglion
● Vagus nerve
● Superior laryngeal nerve
● Hypoglossal Nerve
● Spinal Accessory Nerve
● Glossopharyngeal Nerve
● Stylopharyngeus muscle
Part II of lab – Disarticulation of
Skull from Vertebral Column
Rectus capitus
lateralis
Atlas (C1)
Rectus capitus
anterior
Jugular
foramen
Cut behind mastoid
process
C1
nuchal
ligament
anterior
longitudinal
ligament
C7
post. atlanto-occipital
membrane