Anatomy III: Blood and the Cardiovascular and Respiratory Systems

Larynx, Thyroid and Parathyroid

CEU
Universidad
Cardenal Herrera
2Larynx

• Organ for respiration and voice
  production
• It consists of nine cartilages connected
  by membranes and ligaments
  . It is located at the level of C3-C6
  . It connects the oropharynx with the
  trachea
• It also protects the airway during
  swallowing with a valve-like mechanism
  MAKE GIFS AT GIFSOUP.COM

CEU
Universidad
Cardenal Herrera
3Laryngeal skeleton
Nine cartilages:

• Unpaired cartilages:
  - Thyroid
  - Cricoid
  - Epiglottis
  · Paired cartilages:
  - 2 Arytenoid
  - 2 Corniculate
  - 2 Cuneiform
  Thyroid cartilage
  Superior horn
  Superior
  thyroid
  notch
  Laryngeal
  prominence
  Lamina
  Oblique line
  Median
  cricothyroid
  ligament
  Inferior horn
  Cricothyroid
  Capsule of
  cricothyroid joint
  Cricoid
  cartilage
  Trachea
  Recurrent
  laryngeal nerve
  Tokubb

CEU
Universidad
Cardenal Herrera
4Thyroid cartilage
· The largest of the cartilages

• Located at the level of C4
  . It consists in two flat laminae that will
  fuse in the median plane forming the
  "Adam's apple" or laryngeal
  prominence. It is more prominent in
  men than in women
  · The superior border of the laryngeal
  prominence forms a V that is called
  superior thyroid notch
  Lateral thyrohyoid ligaments
  Right lamina
  Left lamina
  Superior
  thyroid notch
  -Superior
  horn
  Superior
  thyroid
  tubercle
  Oblique line
  Laryngeal
  prominence
  Inferior horn
  Inferior thyroid
  notch
  Inferior thyroid tubercle
  Facet for cricoid
  (medial surface
  of horn)

CEU
Universidad
Cardenal Herrera
5Thyroid cartilage
The posterior border has four
prominences called the superior and
inferior horns
Between the superior horns and the
hyoid bone there is the thyrohyoid
membrane
. Its middle line is very thick and forms
the median thyrohyoid ligament
· Both lateral borders are also very
thick and form the lateral
thyrohyoid ligaments
The inferior horns articulate directly with
the cricoid cartilage: cricothyroid
joints, that allow the rotation of the
cartilages for lengthen or shorten the
vocal folds
Body of hyoid
Median
thyrohyoid
ligament
Greater cornu
of hyoid
Lateral thyrohyoid
ligament
Thyrohyoid
membrane
Cartilago triticea
Thyroid notch
Superior cornu
Laryngeal
prominence
Laminae of
thyroid cartilage
Median
cricothyroid
ligament
Lateral thyrohyoid
ligament
Anterior arch of
cricold
Inferior cornu
Cricotracheal
ligament
First tracheal
cartilage

Thyrohyoid Membrane and Ligaments

CEU
Universidad
Cardenal Herrera
6Thyrohyoid membrane

• Thyrohyoid membrane: from the
  thyroid cartilage to the hyoid bone
  - It has a hole for superior laryngeal
  artery and the internal branch of
  superior laryngeal nerve
  - It makes the median and lateral
  thyrohyoid ligaments
  · Triticeal cartilage: small cartilage
  sometimes appears in the lateral
  thyrohyoid ligament
• Check in this picture the hyo-epiglottic
  ligament and the crico-tracheal
  ligament
  Hyo-epiglottic ligament
  Hyoid bone
  Lateral thyrohyoid ligaments
  Triticeal
  cartilage
  Aperture for
  internal branch of
  superior laryngeal
  nerve and
  associated artery
  Thyrohyoid
  membrane
  Median thyrohyoid
  ligament
  Cricotracheal ligament

Cricoid Cartilage Structure

CEU
Universidad
Cardenal Herrera
7Cricoid cartilage
Shape and size of a ring
· Posterior part: lamina, like the signet of
the ring

• Anterior part: arch, which is complete
  - Check that there is not a complete arch
  at the tracheal rings or the thyroid
  cartilage. Cricoid is the only complete
  cartilaginous ring of the airway
  . Median crico-thyroid ligament: from
  cricoid to the thyroid cartilage
  · Crico-tracheal ligament: from cricoid to
  the first tracheal ring
  Side oblique view
  Back view
  Anterior
  arch
  Facet for
  thyroid
  cartilage
  Facet for
  arytenoid
  cartilage
  Lamina
  Facet for
  thyroid
  cartilage
  Top view
  Lamina
  Anterior arch

Cricoid Cartilage Articulations

CEU
Universidad
Cardenal Herrera
8Cricoid cartilage

• The posterior surface of lamina has:
  - Two oval depressions: for the posterior
  crico-arytenoid muscles
  - One ridge in the middle: for attachment
  of esophagus
• On the sides of cricoid there are:
  - One facet for articulate with the base of
  arytenoid cartilage
  - One facet for the articulation with the
  inferior horn of thyroid cartilage
  Facet for articulation with
  arytenoid cartilage
  Ridge
  Facet for articulation
  with inferior horn of
  thyroid cartilage
  Depressions
  Lamina
  Cricoid
  cartilage
  Facet for
  articulation with
  arytenoid cartilage
  Arch
  Airway
  Facet for
  articulation with
  inferior horn of
  thyroid cartilage
  Trachea

Arytenoid Cartilages Anatomy

CEU
Universidad
Cardenal Herrera
9Arytenoid cartilages
· Shape of a tetrahedron
. They articulate laterally with the cricoid lamina at its superior border
· Apex: superior vertex, attached to the ary-epiglottic fold. The apex holds the
corniculate cartilages
· Vocal process: located at the anterior surface, it is the posterior attachment
for the vocal ligament
· Muscular process: located laterally, it is a lever that provides attachment to
the posterior and lateral crico-arytenoid muscles

Arytenoid Cartilages Movements

CEU
Universidad
Cardenal Herrera
10Arytenoid cartilages
· Crico-arytenoid joints: unites the bases of the
arytenoid with the supero-lateral surface of the
cricoid lamina
. They allow three movements for the arytenoid,
important for tense the vocal folds
- To approach or separate one to each other
- To tilt antero-posteriorly
- To rotate

Arytenoid Cartilages Detailed View

CEU
Universidad
Cardenal Herrera
11Arythenoid cartilages
1 2
2
2
-1
10
4
8
1
/
-5
5
9
7
Lateral view
Medial view
Posterior view
1.
Corniculate cartilage
2.
Apex
3.
Anterolateral surface
4.
Vocal process for vocal ligament
5.
Muscular process for the posterior and
lateral crico-arytenoid muscles
6.
Oblong fovea por the thyro-arytenoid
muscle
7.
Base
8.
Medial surface
9.
Articular surface
10. Posterior surface

CEU
Universidad
Cardenal Herrera
12

Epiglottic Cartilage Location

3 4
6
5Epiglottic cartilage

• Shape of a tennis racket, covered with mucous
  membrane
  . It is the superior part of the anterior wall of the
  laryngeal inlet
  · It is located:
  - Posterior to the root of the tongue and hyoid
  bone
  - Anterior to the laryngeal inlet
  · Its superior border is free
• Its inferior border or stalk lies at the angle
  formed by the thyroid laminae and the thyro-
  epiglottic ligament
• Hyo-epiglottic ligament: from the anterior
  surface of the epiglottis to the hyoid bone
  Anterior surface
  of epiglottis
  Posterior surface
  of epiglottis
  Right thyroid
  lamina
  Epiglottic
  tubercle
  Cricoid
  Thyro-epiglottic
  ligament
  Trachea

Epiglottic Cartilage and Ligaments

CEU
Universidad
Cardenal Herrera
13Epiglottic cartilage
Stalk
Thyro-epiglottic ligament
Thyroid cartilage
IE
Median
cricothyroid
ligament
Arch of cricoid
cartilage
Vocal
process
Vocal
ligament
Arytenoid
cartilage
Apex
Lateral
cricothyroid
ligament
Muscular
process
Corniculate cartilage
Lamina of cricoid cartilage
Rima glottidis
Capsule of crico-arytenoid
joint
Conus
elasticus

Corniculate and Cuneiform Cartilages

CEU
Universidad
Cardenal Herrera
14Corniculate and Cuneiform
They are small nodules in the posterior
wall of the ary-epiglottic folds

• Corniculate: attached to the apex of
  the arytenoid
• Cuneiform: they do not attach to
  other cartilages. They are in the
  middle of the quadrangular
  membrane
  Epiglottic cartilage
  Quadrangular membrane
  Vestibular ligament
  Cuneiform cartilage
  Superior horn of
  thyroid cartilage
  Corniculate cartilage
  Arytenoid cartilage, medial surface
  Posterior crico-arytenoid ligament
  Vocal process of arytenoid cartilage
  Vocal ligament
  Lateral cricothyroid ligament
  Conus
  elasticus
  Surgical needle spreading halves of cricoid cartilage
  Tracheal ring

Submucosal Membrane of the Larynx

CEU
Universidad
Cardenal Herrera
15Submucosal membrane of the larynx
It consists on two parts:

• Superior part: quadrangular
  membrane, it is located between the
  arytenoid and epiglottis at their lateral
  aspect
  - Its superior border is the ary-
  epiglottic ligament/fold
  - Its inferior border is the vestibular
  ligament/fold, the "false vocal
  cord"
  · They go from the arytenoid
  cartilage to the thyroid angle
  · The ligaments are superior and
  lateral to the vocal folds or "true
  vocal cords"
• Inferior part: conus elasticus
  Quadrangular membrane
  Epiglottis
  Vocal ligament
  Vestibular
  ligament
  Cricothyroid ligament
  Vocal process of arytenoid
  Muscular process
  of arytenoid
  Corniculate cartilage

Quadrangular Membrane Structures

CEU
Universidad
Cardenal Herrera
16Check the structures of the quadrangular membrane
We say "fold" to emphasize that the "ligament" is covered with mucosa
Epiglottis
Epiglottic cartilage
Ary-epiglottic fold
Quadrangular membrane
Cuneiform tubercle
Vestibular ligament
Corniculate tubercle
Cuneiform cartilage
Superior horn of
thyroid cartilage
Corniculate cartilage
Arytenoid (cut surface)
Arytenoid cartilage, medial surface
Posterior crico-arytenoid ligament
Vestibular fold
Ventricle
Vocal process of arytenoid cartilage
Vocal fold
Vocal ligament
Conus
Lateral cricothyroid ligament elasticus

Conus Elasticus and Ligaments

CEU
Universidad
Cardenal Herrera
17Conus elasticus
Conus elasticus or Cricovocal membrane:
membrane that completes the laryngeal hole
when the vocal ligaments are closed
. It has two thick parts that become
ligaments:

• Vocal ligaments itself, which are the
  superior border of the membrane
• Lateral cricothyroid ligaments:
  lateral ligaments from the vocal folds to
  the superior border of the cricoid
• Anteriorly, the membrane fuses with the
  median cricothyroid ligament
  - It is a good place for emergency
  tracheostomy because there are few
  structures between the skin and it
  Vocal ligament
  Cricothyroid ligament
  Median cricothyroid ligament

Conus Elasticus Diagram

CEU
Universidad
Cardenal Herrera
18Conus elasticus
Epiglottic cartilage
Stalk
Thyro-epiglottic ligament
Thyroid cartilage
Arch of cricoid
cartilage
Median
cricothyroid
ligament
Vocal
process
Vocal
ligament
Arytenoid
cartilage
Apex
Lateral
cricothyroid
ligament
Muscular
process
Corniculate cartilage
Rima glottidis
Capsule of crico-arytenoid
joint
Lamina of cricoid cartilage
Conus
elasticus

Vocal Ligaments and Folds

CEU
Universidad
Cardenal Herrera
19Vocal ligaments
Vocal ligaments # Vocal folds
Vocal ligaments are the frame
of the vocal folds. When the
ligament is covered by the
mucosa, then we speak about
vocal fold
Insertions:

• Anterior: the middle line
  of the thyroid cartilage
  lamina
• Posterior: the vocal
  process of the arytenoid
  Epiglottic cartilage
  Stalk
  Thyro-epiglottic ligament
  Thyroid cartilage
  Arch of cricoid
  cartilage
  Median
  cricothyroid
  ligament
  Vocal
  process
  Vocal
  ligament
  Arytenoid
  cartilage
  Apex
  Conus
  elasticus
  Muscular
  process
  Lateral
  cricothyroid
  ligament
  Corniculate cartilage
  Rima glottidis
  Capsule of crico-arytenoid
  Lamina of cricoid cartilage
  joint

CEU
Universidad
Cardenal Herrera
20