Larynx pdf - غير معروف

Head & Neck

 Ear

 Larynx

 Oral Cavity

 Nose

Done by:

Abbas Fadel

Group C

The Larynx:
The larynx lies in the anterior part of the neck in the
midline  opposite  to  C4-C6  vertebrae  forming  the
laryngeal prominence (Adam’s apple)
At  this  level  the  L.  is  triangular  in  cross  section
while  lower  down  at  the  level  of  the  cricoid
cartilage it is circular in cross section
Relations:
- Anterolaterally; Thyroid gland & strap muscles
- Laterally; Carotid sheath
- Posteriorly; Pharynx
Skeleton:
The thyroid cartilage:

• This hyaline cartilage is composed of two

quadrilateral laminae meet in the midline

• The meeting angle is 90O in male & 120O in

female (therefore the L is more prominent in
male)

• The superior thyroid notch is a V-shape notch just above the prominence
• The posterior border of the cartilage is thick & rounded & extends above &

below the laminae as the superior & inferior horns

• The superior & inferior borders are characterized by superior & inferior

tubercles between them the oblique line of the cartilage extends which gives
attachment to thyrohyoid, sternothyroid & thyropharyngeus

• The upper border is attached to the thyrohyoid membrane which is thickened

in the midline as the median thyrohyoid ligament & thickened laterally
between the superior horn & tip of greater horn of the hyoid as the lateral
thyrohyoid ligament

• The inferior thyroid notch lies opposite to the superior one, from its deep

surface the root of the epiglottis arises

The cricoid cartilage: the only complete ring in the respiratory pathway

• This signet ring-like cartilage is characterized by an anterior arch &

posterior broad lamina

• It lies at the level of C6 vertebra & forms the

foundation on which the rest of the larynx is
built

• The posterior lamina is marked in the

midline by a ridge on either side of which
lies a shallow depression for the posterior
crico-arytenoid muscle

• The arch which is 5 mm in vertical height

gives attachment anterolaterally to crico-
thyroid muscle & posteriorly to the
cricopharyngeus just above which the lateral
crico-arytenoid arises

• The upper border of the arch gives

attachment to the conus elasticus

• The sloping shoulders of the lamina

provides a synovial joint for the
arytenoid cartilages

• At the junction of the arch & lamina is

a synovial joint for articulation of the
inferior horns of the thyroid cartilages

The arytenoid cartilage:

• This is a three sided pyramidal hyaline

cartilage whose apex projects
posteromedially & carries the
corniculate cartilages

• The base of the pyramid carries three

processes

• The anterior sharp process is the vocal

process & to which the upper free end
of the conus elasticus is attached as the
vocal fold

• The lateral process is the muscular

process to which the lateral &
posterior crico-arytenoids are attached

• The medial surface of the pyramid is

flat & faces the opposite one

Ridge

Depression for the post. Crico-arytenoid

• The anterolateral surface is curved & gives attachment for the thyro-

arytenoid muscle

• The posterior surface is smooth & gives attachment for the transverse

arytenoid muscle

• The arytenoid cartilage sits on the elongated facet on the sloping shoulder of

the cricoid lamina forming the crico-arytenoid synovial joint

The corniculate cartilage:

• This small nodular elastic cartilage lies on the apex of

the arytenoid to prolong it backward & medialward

• They are enclosed by the ary-epiglottic folds

The cuneiform cartilage:

•A r e r o d l i k e e l a s t i c
cartilages lies on the previous
ones in the ary-epiglottic
folds

The epiglottis:

•This elastic, leaf-like

cartilage  is  attached  by  its
lower  1/2  to  the  back  of  the
thyroid  cartilage  by  the
thyro-epiglottic  ligaments  in
the midline, its upper 1/2 stands erect behind the
posterior 1/3 of the tongue & the hyoid bone

• The anterior surface of the epiglottis is attached to the hyoid bone by the

hyo-epiglottic ligament

• The m.m of the E. is reflected on the posterior 1/3 of the tongue as three

folds,  the  median  &  two  lateral  glosso-epiglottic  folds  which  mark  the
division  between  the  oro-  &  laryngo-pharynx,  on  each  side  of  the  median
one lies a vallecula

• The cartilage is well pitted to receive the multiple mucous glands which

cover it

• To the margins of the free upper ½ is attached the quadrate membrane

Vallecula

Laryngeal membranes:
1-Thyro-hyoid membrane:

- Suspends the thyroid cartilage to the

hyoid bone

- It passes from the upper border of the

thyroid cartilage to the upper border of
the hyoid bone passing behind the bone
separated from it by a bursa

- It shows one median & two lateral

ligaments of the same name

- It is pierced by the superior laryngeal

artery & internal laryngeal nerve.

- It forms the lateral boundary of the

piriform recess

2- Conus elasticus:

- Is a half-circle ligament whose lower

attachment is to the whole length of
the upper border of the cricoid arch

- Its free upper border is attached on

either side to the vocal process of the
arytenoid  cartilage  forming  the  vocal
fold  (true  vocal  cord)  which  contains
in  its  free  border  muscle  fibers
(vocalis)

- Anteriorly the membrane is attached

to the back of the thyroid cartilage in
the angle between the two laminae in

Internal laryngeal nerve

Vocal fold

the midline midway between the superior & inferior notches converting the
curved membrane to V-shape membrane

- Its thickening in the midline anteriorly produces the median crico-thyroid

ligament

3- Quadrate membrane:

- Is a weak membrane whose posterior

border is attached to the anterior
surface of the arytenoid cartilage & its
anterior border is attached to the sides
of the lower half of the epiglottis

- Its upper free border will extend

between the epiglottis & the arytenoid
cartilage forming the ary-epiglottic fold
which involves in its substance the
corniculate & cuneiform cartilages

- Its lower free border will be parallel to

the upper free border of the conus (true
vocal cords) forming the vestibular fold
(false cords)

- It forms the medial boundary of the

piriform recess

The interior of larynx:
The laryngeal inlet:

- Opens in the anterior wall of the

Crico-thyroid ligament

Vocal ligament

Arytenoid cartilage

Corniculate cartilage

Ary-epiglottic fold

False vocal fold

pharynx in a vertical plane

- Is an inverted triangle whose base is formed

by the epiglottis antero-superiorly & its apex
is the narrow interval between the two
arytenoids postero-inferiorly

- The sides of the triangle is the ary-epiglottic

olds

The laryngeal vestibule:

- Is the triangular cavity beyond the laryngeal

inlet until the rima glottidis

- It is bounded on each side by the quadrate

membrane

- It shows three features:

1-  The  vestibular  folds;  are  the  lower  free  border
of the quadrate membranes
2-  The  laryngeal  ventricle;  is  a  sac  like  mucosal
herniation  between  the  true  &  false  vocal  folds
whose upper border extends up & may reach the
upper  border  of  the  thyroid  cartilage,  it  is  filled
with mucosal glands for lubrication

3- The rima vestibuli; is the opening between the vestibular folds, it is wider than
the rima glottidis.
The vocal folds:

- Are formed by the free upper border of the conus stretched between the

thyroid cartilage anteriorly & the arytenoids posteriorly

- The anterior 3/5 are true components of the conus while the posterior 2/5 are

formed by the vocal process of the
arytenoids

- They contain in their free edge the vocalis

muscle which increases the apposed
surface area of the cords during phonation

- The opening between them is called the

rima glottidis

- Glottis, is a term applied to the two vocal

cords & the rima glottidis as they are the
main structure involved in phonation

The rima glottidis:

- Is the interval between the two

vocal cords

- Is 23 mm long in male & 17 mm

in female

- It could be opened either in V-

shape or diamond shape manner
a c c o r d i n g t o t h e t y p e o f
movement of the arytenoid

- Downward movement of the

a r y t e n o i d  o n  t h e  s l o p i n g
shoulders  of  the  cricoid  lamina
pulls  the  two  ends  of  the  conus
downward  separating  them  &
opens  the  rima  in  a  V-shape  manner,  here  the  vocal  processes  of  the
arytenoids are parallel to each other, this occurs in quite respiration

- Rotation of the arytenoids around their vertical axes

pulls the free ends of the conus away & opens the
rima  in  a  diamond  shape  manner,  the  back  of  the
diamond  is  formed  by  the  vocal  processes  of  the
arytenoids  which  become  perpendicular  on  each
other, this occurs in forced respiration

- During phonation the folds come in contact with

each other & the rima becomes slit like

Intrinsic muscles:
The ary-epiglottic muscle:

- Extends in the ary-epiglottic fold from the

arytenoids to the lateral border of the epiglottis

- The oblique inter-arytenoids are regarded as the

continuation of the muscle to the vocal process of
the opposite arytenoid

- Contraction of both brings the arytenoids near each

other  &  oppose  the  ary-epiglottic  folds  &  pull  the
epiglottis  as  a  shelf  over  the  constricted  laryngeal
inlet  producing  an  effective  sphincteric  action  for
the inlet

The  posterior  crico-arytenoid:  the  only  muscles  open
vocal folds
Origin; from the back of cricoid lamina from the fossa on
each side of the midline ridge
Insertion; upper fibers go horizontally to the vocal process of the arytenoid while
the lower fibers go vertically to the to the same process
Action;  upper  fibers  rotate  the  arytenoids  so  they  open  the  rima  glottidis  in  a
diamond  shape  while  the  lower  fibers  pull  the
arytenoids away from each other so they open the
rima in a V-shape
The transverse arytenoid:

- This is a muscle formed of fine & short

fibers stretched between the two arytenoids
deep to the oblique one

- Its contraction opposes the vertical fibers

of the posterior c-a muscle ﻣﻬﻢ

The lateral crico-arytenoid:

- Arises from the posterior part of the

cricoid arch

- Inserted into the vocal process of the

Thyroarytenoid

Aryepiglottic

Late

ral cri

co a

ryten

oid

arytenoid

- Its contraction opposes the horizontal fibers of the posterior c-a muscle

The crico-thyroid:

- This muscle arises from the anterolateral surface of the cricoid arch
- Its fibers radiate upward & backward to be inserted into the lower border &

medial aspect of the thyroid cartilage

- Its contraction approximates the thyroid & cricoid cartilages diminishing the

area between them, this will bring the thyroid cartilage away from the
arytenoid increasing the length & hence tension of the vocal cords affecting
consequently the type of the voice

The thyro-arytenoid: page 9

- This muscle arises from the inner surface of the thyroid lamina
- Its fibers pass backward to be inserted into the muscular process of the

arytenoid

- Its contraction approximates the thyroid & arytenoid cartilages diminishing

the area between them, this will decrease the length & hence tension of the
vocal cords affecting consequently the type of the voice, this movement also
acts as a laryngeal sphincter

Arteries of the larynx:
1- Superior laryngeal artery;

- A branch of the superior thyroid a.
- pierces the thyrohyoid membrane together

with  the  internal  laryngeal  nerve  to  lie
underneath  the  m.m  of  the  floor  of  the
piriform recess

- supplies the larynx to supply mucosa down

to the level of the vocal cords.

2 -
Inferior laryngeal artery;
-A  branch  of  the  inferior  thyroid
artery
-enters  the  lower  part  of  the
larynx  deep  to  the  inferior
pharyngeal constrictor
-supplies  it  up  to  the  vocal  cords
(vocal  cords  are  supplied  by  the
inferior one).
-

-Nerves of the larynx:
-Motor:
-All muscles of the larynx are

supplied by the recurrent laryngeal

n.  except  cricothyroid  which  is
supplied  by  the  external  laryngeal
branch  of  the  superior  laryngeal  nerve
(X nerve).
-Sensory:
•Above  the  vocal  folds  :  internal
laryngeal  branch  of  superior  laryngeal
nerve  (X  nerve)  accompanies  the  sup.
laryngeal artery.
•Below  the  vocal  folds:  recurrent
laryngeal  nerve  accompanies  the
inferior laryngeal artery

Sup. thyroid artery

Sup. laryngeal artery

Internal
branches
of sup.
laryngeal
nerve ,
artery and
vein