Pharynx & Larynx
Muhammad Ishaq Anwar
(Cardiology)
KMU-IPMS
Pharynx
• A muscular tube that connects the oral and nasal
cavity to the larynx and esophagus.
• Begins at the base of the skull and ends at the
inferior border of the cricoid cartilage (C6).
• Upper end is wider, and lower end is narrow and
continue with esophagus.
• Has musculomembranus wall which is deficient
anteriorly and replaced by posterior opening into
nose called choanae.
• Continuous to tympanic cavity via auditory tube.
• Length is about 12-14cm.
Parts of Pharynx
• Comprised of three parts
(superior to inferior):
✓Nasopharynx
✓Oropharynx
✓Laryngopharynx
Nasopharynx
• lies above the soft palate and behind the nasal cavities
• In the submucosa of the roof is a collection of lymphoid tissue called the
pharyngeal tonsil
• The pharyngeal isthmus is the opening in the floor between the soft palate
and the posterior pharyngeal wall.
• On the lateral wall is the opening of the auditory tube, the elevated ridge of
which is called the tubal elevation( torus tubarius).
• The pharyngeal recess is a depression in the pharyngeal wall behind the tubal
elevation.
• The salpingopharyngeal fold is a vertical fold of mucous membrane which
extends downward tubal elevation covering the salpingopharyngeus muscle.
Oropharynx
• The oropharynx is the middle part of the pharynx, located between the soft palate and the superior
border of the epiglottis.
• It contains the following structures:
Posterior one third of the tongue.
Lingual tonsils lymphoid tissue at the base of the tongue.
Palatine tonsils lymphoid tissue located in the tonsillar fossa (between the palatoglossal and palatopharyngeal arches of the
oral cavity).
Superior constrictor muscle
• The median glossoepiglotic fold is in the midline, and the lateral glossoepiglotic fold is to the side.
• The depression on each side of the median glossoepiglotic fold is the vallecula.
• The palatoglossal and palatopharyngeal arches or folds are on the lateral wall.
• Oropharyngeal isthmus is the interval b/w paired palatoglossal arches and marks the boundary b/w
mouth and pharynx.
• Palatoglossal and palatopharyngeal arches cover the palatoglossal and palatopharyngeal muscle
respectively.
Waldeyer’s ring is the ring of lymphoid tissue in the naso- and oropharynx formed by the paired palatine
tonsils, the adenoid tonsils and lingual tonsil.
The oropharynx is involved in the voluntary and involuntary phases of swallowing.
laryngopharynx
• lies behind the opening into the larynx.
• lateral wall is formed by the thyroid
cartilage and the thyrohyoid membrane.
• Medial wall is formed by aryepiglottic
fold.
• The piriform fossa is a depression in the
mucous membrane on each side of the
laryngeal inlet
• Specifically, it refers to the point at which
the pharynx divides anteriorly into the
larynx and posteriorly into the esophagus
• The laryngopharynx contains the middle
and inferior pharyngeal constrictors
Pharyngeal constrictors and longitudinal muscles
There are six pharynx muscles in total that can be divided into two groups:
• Pharyngeal constrictors
• Superior
• Middle
• Inferior
•Pharyngeal raphe is a fibrous band that extends from the pharyngeal tubercle on the basilar part
of the occipital bone of the skull down to the esophagus and the 3 constrictors insert into this
band.
•The lower part of the inferior constrictor, which arises from the cricoid cartilage, is called the
cricopharyngeus muscle.
•The Killian dehiscence is the area on the posterior pharyngeal wall between the upper
propulsive part of the inferior constrictor and the lower sphincteric part, the cricopharyngeus.
•Longitudinal muscles
• Palatopharyngeus
• Salpingopharyngeus
• Stylopharyngeus
Nerve Supply of the Pharyngeal Mucous Membrane
Sensory
• Nasal pharynx: The maxillary nerve (V2)
• Oral pharynx: The glossopharyngeal nerve
• Laryngeal pharynx (around the entrance into the larynx): The internal laryngeal branch of the
vagus nerve
Motor
• All the muscles of the pharynx are innervated by the vagus nerve (CN X), except for the
stylopharyngeus, which is innervated by the glossopharyngeal nerve (CN IX)
Blood Supply of the Pharynx
Arterial supply to the pharynx is via branches of the external carotid artery:
• Ascending pharyngeal, tonsillar branches of facial arteries, and branches of maxillary and lingual
arteries
• Venous drainage is achieved by the pharyngeal venous plexus, which drains into the internal
jugular vein
Lymph Drainage of the Pharynx
• Directly into the deep cervical lymph nodes or indirectly via the retropharyngeal or paratracheal
nodes into the deep cervical nodes
Larynx
Larynx
• A tube shape cartilaginous structure present anteriorly in neck
• The larynx is composed of three large unpaired cartilages (cricoid, thyroid,
and epiglottis) and three paired smaller cartilages (arytenoid, corniculate,
and cuneiform), making a total of nine individual cartilages.
• Located between the pharynx and trachea
• Suspended from the hyoid bone and Spanning between C3-C6 Cervical
vertebra approximately 5cm
• Larynx in front is covered by Infrahyoid strap muscle and at sides by
thyroid gland.
• The larynx is formed by a cartilaginous skeleton, which is held together by
ligaments and membranes. The laryngeal muscles act to move the
components of the larynx for phonation and breathing
Larynx
• Anatomically, the internal cavity of the larynx can be divided into
three sections:
Supraglottis: between the laryngeal inlet and the vestibular folds (false vocal
cords).
Glottis: Area of vocal cords. Middle part, between the vestibular folds
above and vocal folds below
Subglottis: between the vocal fold and the trachea
Larynx
• Relation
• Superiorly: Hyoid bone and root of the tongue
• Inferiorly: Trachea
• Anteriorly: Infrahyoid muscles
• Posteriorly: C3-C6 Cervical vertebra and Laryngopharynx
• Laterally: Bilateral lobes of thyroid gland
Cartilages of Larynx
Thyroid cartilage:
• Largest cartilage of the larynx and consists of two laminae of hyaline cartilage that meet
in the midline in the prominent V angle ( Adam's apple).
• Posterior border extends upward into a superior cornu and downward into an inferior
cornu.
• Superior horns are connected to the hyoid bone via the lateral thyrohyoid ligament,
while the inferior horns articulate with the cricoid cartilage.
• On the outer surface of each lamina is an oblique line for the attachment of muscles.
Cricoid cartilage:
• Formed by hyaline cartilage and shaped like a signet ring, having a broad plate behind
and a shallow arch in front.
• Lies below the thyroid cartilage, and on each side of the lateral surface is a facet for
articulation with the inferior cornu of the thyroid cartilage.
Thyroid Cartilage
Thyroid Cartilage
Cricoid Cartilage
Cartilages of Larynx
Epiglottis
• leaf shaped plate of elastic cartilage which marks the entrance to the larynx.
• Its ‘stalk’ is attached to the back of the anterior aspect of the thyroid cartilage.
• During swallowing, the epiglottis flattens and moves posteriorly to close off the larynx and
prevent aspiration.
• The sides attached to the arytenoid cartilages by the aryepiglottic folds of mucous
membrane.
• The upper edge of the epiglottis is free.
• The covering of mucous membrane passes forward onto the posterior surface of the
tongue as the median glossoepiglottic fold.
• depression on each side of the fold is called the vallecula
• Laterally, the mucous membrane passes onto the wall of the pharynx as the lateral
glossoepiglottic fold.
Epiglottis Cartilage
Cartilages of Larynx
Arytenoid Cartilages
• The arytenoid cartilages are pyramidal shaped structures that sit on the
cricoid cartilage.
✓ Apex: articulates with the corniculate cartilage.
✓ Base: articulates with the superior border of the cricoid cartilage.
✓ Vocal process: provides attachment for the vocal ligament.
✓ Muscular process: provides attachment for the posterior and lateral cricoarytenoid
muscles.
Arytenoid Cartilage
Cartilages of Larynx
Corniculate Cartilages
• Two small conical-shaped cartilages articulate with the arytenoid
cartilages.
• give attachment to the aryepiglottic folds
Cuneiform Cartilages
• Two small rod-shaped cartilages are found in the aryepiglottic folds and
serve to strengthen them
Corniculate Cartilage
Cuneiform Cartilage
Joints of Larynx
• Larynx contain two pairs of joints:
✓ Cricothyroid Joint – joint b/w inferior cornu of thyroid cartilage and the
lateral side of cricoid cartilage
✓ Cricoarytenoid joint – joint b/w base of arytenoid cartilage and the
superior border of the lamina of the cricoid cartilage.
Both joints are synovial and allow multiaxial movement of rotation
and gliding.( these movements occur simultaneously or independently)
Lamina of cricoid cartilage
Cricoarytenoid Joint
Cricothyroid Joint
Membranes and Ligaments of Larynx
The laryngeal membranes and ligaments support the cartilaginous skeleton of the larynx.
The extrinsic ligaments act to attach the components of the larynx to external structures (such as
the hyoid and the cricoid cartilage). The intrinsic ligaments are responsible for holding the
cartilages of the larynx together as one functional unit internally
Extrinsic
Intrinsic
• Thyrohyoid membrane
• Hyo-epiglottic ligament
• Cricotracheal ligament
• Median cricothyroid ligament
• Cricothyroid ligament
• Quadrangular membrane
Membranes and Ligaments of Larynx
Thyrohyoid membrane:
• This connects the upper margin of the thyroid cartilage to the hyoid bone.
• In the midline, it is thickened to form the median thyrohyoid ligament.
• Lateral thyrohyoid ligaments is a Posterolateral thickenings of the membrane
• The membrane is pierced on each side by the superior laryngeal vessels and
the internal laryngeal nerve, a branch of the superior laryngeal nerve.
Quadrangular membrane:
• This extends between the epiglottis and the arytenoid cartilages.
• Its thickened inferior margin forms the vestibular ligament, and the vestibular
ligaments form the interior of the vestibular folds
Membranes and Ligaments of Larynx
Cricothyroid ligament
• Originates from the cricoid cartilage and extends superiorly, where it terminates with
an free (unattached) upper margin which forms the vocal ligament.
• The vocal ligaments form the interior of the vocal folds (vocal cords)
• It is additionally attached anteriorly to the thyroid cartilage, and posteriorly to the
arytenoid cartilage.
Cricotracheal ligament:
• This connects the cricoid cartilage to the first ring of the trachea.
Hyo-epiglottic ligament:
• Connects the hyoid bone to the anterior aspect of the epiglottis.
Median cricothyroid ligament:
• Anteromedial thickening of the cricothyroid ligament, connecting the thyroid and
cricoid cartilages.
Quadrangular membrane
Cricotracheal ligament
Cricothyroid ligament
Thyroepiglottic Ligament
Internal Features of Larynx
Laryngeal Inlet:
• Opening from the pharynx to larynx.
• Formed by epiglottis and aryepiglottic fold.
• Bounded in front by epiglottis, laterally by aryepiglottic fold and posteriorly by
arytenoid cartilage with corniculate cartilage.
• The cuneiform cartilage lies within and strengthens the aryepiglottic fold and
produces a small elevation on the upper border.
Piriform Fossa:
• Recess present on each side of inlet and bounded medially by aryepiglottic fold and
laterally by thyroid cartilage + thyrohyoid membrane.
Laryngeal Folds
Two important soft tissue folds located within the larynx, vestibular folds and
vocal folds. They play a crucial role in protection of the airway, breathing, and
phonation.
Vestibular fold
• The vestibular fold is a fixed fold on each side of the larynx.
• It is formed by mucous membrane covering the vestibular ligament and is
vascular and pink in color.
• Also called false vocal cords lie superiorly to the true vocal cords.
• Provide protection to the larynx.
Vestibular fold
Vocal fold
Laryngeal saccule
Laryngeal Folds
Vocal Fold (Vocal Cord)
• True vocal cords
• Mobile fold on each side of the larynx and is concerned with voice production.
• Formed by mucous membrane covering the vocal ligament.
• Avascular and white in color.
• Moves with respiration and its white color is easily seen when viewed with a
laryngoscope.
• Gap between the vocal folds is called the rima glottidis or glottis.
• Glottis is bounded in front by the vocal folds and behind by the medial surface of the
arytenoid cartilages.
• Glottis is the narrowest part of the larynx and measures about 2.5 cm from front to back
in the male adult and less in the female.
• In children, the lower part of the larynx within the cricoid cartilage is the narrowest part.
Laryngeal Cavity
• Cavity (lumen) extends from inlet to the lower border of cricoid cartilage.
• It is divided into three regions:
Vestibule or Upper Region:
• Area b/w inlet and vestibular fold.
Middle Region:
• Is a central space b/w opposite vestibular fold and vocal folds.
• Contain a recess b/w ventricular fold above and vocal fold below called ventricle.
• From ventricle a mucous membrane line diverticulum ascends called saccule.
Infraglottic cavity or Lower Region:
• Is area b/w vocal folds above and lower border of cricoid cartilage below.
Muscles of the Larynx
Extrinsic muscles
• These muscles move the larynx up and down during swallowing.
• Many of these muscles are attached to the hyoid bone, which is attached to the thyroid
cartilage by the thyrohyoid membrane.
• It follows that movements of the hyoid bone are accompanied by movements of the
larynx.
Elevation: digastric, stylohyoid, mylohyoid, Geniohyoid, the stylopharyngeus,
salpingopharyngeus, And the palatopharyngeus muscles
Depression: sternothyroid, sternohyoid, and
Omohyoid muscles
Muscles of the Larynx
Intrinsic Muscles
• Two muscles modify the laryngeal inlet:
Narrowing the inlet: The oblique arytenoid muscle
Widening the inlet: The thyroepiglottic muscle
• Five muscles move the vocal folds:
Tensing the vocal cords: The cricothyroid muscle
Relaxing the vocal cords: The thyroarytenoid (vocalis) muscle
Adducting the vocal cords: The lateral cricoarytenoid muscle
Abducting the vocal cords: The posterior cricoarytenoid muscle
Approximates the arytenoid cartilages: The transverse arytenoid muscle
Nerve Supply of the Larynx
• Main supply to whole larynx is through vagus nerve (CN-X) and its branches.
Superior laryngeal nerve (further divides into external and internal laryngeal nerves)
Recurrent laryngeal nerve (become Inferior laryngeal when cross inferior border of cricoid cartilage)
Sensory
• Above the vocal cords: Internal laryngeal nerve
• Below the level of vocal cords: Inferior laryngeal nerve
Motor
• The external laryngeal nerve supplies the cricothyroid muscle.
• The recurrent laryngeal nerve supplies all the intrinsic muscles of the larynx
except the cricothyroid muscle.
Blood Supply & Lymph Drainage of the Larynx
Blood Supply of the Pharynx
• Upper half of the larynx: Superior laryngeal branch of the superior thyroid artery
• Lower half of the larynx: Inferior laryngeal branch of the inferior thyroid artery
Lymph Drainage of the Pharynx
• Directly into the deep cervical lymph nodes
Reference
• Snell Clinical Anatomy