Pharynx And Larynx

Front 1

Pharynx

Back 1

Upper part of digestive and respiratory tracts.

A muscular tube that directs food into the esophagus and conducts air to the larynx and trachea.

Has three parts:
- nasopharynx (space superior to nasal cavity)
- oropharynx (space posterior to oral cavity)
- laryngopharynx (space posterior to larynx)

Front 2

Muscles of the Pharynx

Back 2

- Pharynx is composed of a series of constrictor muscles
- Also, several longitudinal muscles
- Contract, propelling food into esophagus
- Help to elevate pharynx during swallowing and speaking

Front 3

Pharyngeal Constrictors

Back 3

- Superior, middle, inferior constrictors
- They overlap posteriorly, and meet in the posterior midline at the pharyngeal raphe (origin of muscles)

Front 4

Superior Constrictor

Back 4

Shares a common attachment with buccinator: the pterygomandibular raphe, which runs from the pterygoid hamulus to posterior to third molar on mandible.

Front 5

Other constrictors

Back 5

Middle constrictor:
- runs from pharyngeal raphe to hyoid bone

Inferior constrictor:
- from pharyngeal raphe to thyroid/cricoid cartilages
- crycopharyngeus portion forms a sphincter at the superior end of the esophagus.

Front 6

Longitudinal Muscles of the Pharynx

Back 6

- Stylopharyngeus
Goes from styloid process and between constrictors to reach thyroid cartilage.

Salpingopharyngeus:
- salpinx (tube, auditory tube)

Palatopharyngeus (from soft palate to pharynx)

Front 7

Nasopharynx

Back 7

Respiratory part of pharynx. Extends from base of skull down to soft palate.

Auditory tube opens here. Bony and cartilagenous tube connecting middl ear to pharynx. Opened by the action of tensor/levator veli palatini.

Front 8

Oropharynx

Back 8

Connects to oral cavity through the pillars of the fauces (palatoglossal and palatopharyngeal arches)
- food and air pass through here
- extends from soft palate to base of tongue

Posterior 1/3 of tongue resides here.

Front 9

Valleculae

Back 9

Depression between the root of the tongue and the epiglottis.

Glossoepiglottic folds form the borders (one medial, two lateral).

Front 10

Laryngopharynx

Back 10

Found posterior to larynx. Connects to esophagus. Foods and liquids go through here.

Just lateral to this opening of the larynx are outpouchings:
- piriform recesses
- foreign objects can lodge here

Front 11

Tonsils

Back 11

Collection of lymphoid tissue. Form an incomplete circle around the pharyngeal inlet. Tonsils tend to regress with age.

Have both palatine and lingual tonsils.

Front 12

Tonsils - detail

Back 12

Pharyngeal tonsils:
- at the roof of the nasopharynx

Tubal tonsils: around auditory tube ostium

Lingual tonsils: on posterior 1/3 of tongue

Palatine tonsils:
- in the tonsilar fossa, between the pillars of the fauces

Front 13

Tonsillectomy

Back 13

Removal of the palatine tonsils.

Some risks:
- tonsillar bed highly vascularized, excessive bleeding can occur
- damage to glossopharyngeal nerve (altered sensation from posterior tongue)

Front 14

Adenoiditis (in the clicic)

Back 14

Enlarged (inflamed) pharyngeal (and tubal) tonsils:
- may cause breathing difficulties
- blockage of the choanae
- mouth breathers can lead to dental breather

- Can promote middle ear infections and lead to hearing loss (through chronic blockage of auditory tube).

Front 15

Innervation to the Pharynx

Back 15

Motor supply to pharyngeal muscles is from vagus nerve (CN X).
- via pharyngeal plexus
- exception of stylopharyngeus from CN IX, third arch derivative
- sensory supply is from glossopharyngeal nerve (CN IX, but also via pharyngeal plexus)

Front 16

Larynx

Back 16

Voice box.
Opening into the trachea (airway)

Supported by cartilages, membranes, muscles and mucosa.

Front 17

Spaces of the larynx

Back 17

Vestibule: entrance into larynx, space superior to vestibular folds.

Ventricle: between vestibular and vocal folds (cords).

Glottis: vocal cords and the space between the two cords.

Front 18

Laryngeal Folds

Back 18

Vestibular fold: false vocal cord.

Vocal fold:
- contains the true vocal cord

Front 19

Laryngeal Cartilages

Back 19

Thyroid cartilage is shield shaped, connected to hyoid via thyrohyoid membrane.
Thyroid has laryngeal membrane (adam's apple), and thyroid notch down middle.

Cricoid cartilage:
- complete ring of cartilage shaped like signet ring (wide posteriorly) connected to thyroid cartilage by cricothyroid membrane.

Front 20

Arytenoid Cartilages

Back 20

Sit on superior surface of cricoid. Muscular process points laterally, vocal process points anteriorly.

Vocal cord runs from vocal process to inner surface of thyroid cartilage.

Front 21

Epiglottis

Back 21

Leaf shaped cartilage protecting the laryngeal inlet. Separated from tongue by valeculae. Connects to arytenoid cartilages via aryepiglottic folds.

Front 22

Laryngeal Membranes

Back 22

Quadrangular membrane:
between epiglottis and arytenoid cartilages (upper border of aryepiglottic folds and lower border of vestibular ligament i.e. false vocal cord).

Conus elasticus:
from the cricoid to the thyroid cartilages (upper border is true vocal cord

Front 23

Laryngeal Muscles

Back 23

Overy the membranes and cartilages.

Posterior cricoarytenoid muscles open the airway (glottis) and abduct the vocal cords. Only ABDUCTOR of larynx.

The oblique and transverse arytenoid close the airway, and move the vocal cords closer together.

Cricothyroid: connects crycoid to thyroid. Stretches cords, changes pitch of voice. Found in anterior body between those cartilages.

Lateral cricoarytenoid adducts the cords.

Vocalis: fine adjustments of vocal cord.

Front 24

Functions of Larynx

Back 24

1) Close laryngeal inlet: keeps food and other materials out of airway, effort closure of the airway - closing both the vocal and vestibular folds. Do this while taking a dump or lifting things.

Second main function is to move vocal cords. Opens the airway and produces speech.

Front 25

Phonation

Back 25

Produced by vocal folds coming into close contact. Air is forcibly expired between them, making them vibrate.

Changes in pitch and tone produced by contraction of muscles, movement of cartilages, changes in length and thickness of the cords.

Sounds are modified by movements of lips/tongue.

Hormonal changes at puberty cause growth of thyroid cartilage and lengthening of vocal chords leading to changes in pitch of voice in males.

Front 26

Sensory Innervation of larynx

Back 26

Superior to vocal cords, mucosa is supplied by internal laryngeal nerve (from superior branch of vagus, passes through thyrohyoid membrane).

Below the vocal cords, sensation is carried by the recurrent laryngeal nerve.

Front 27

Motor Innervation of larynx

Back 27

Recurrent laryngeal nerve of vagus.

Exception is cricothyroid, which is done by external laryngeal branch of vagus.
Recur around subclavian artery/aortic arch.
Travels up neck between trachea and esophagus.

Front 28

CN IX

Back 28

Glossopharyngeal nerve. Exits via jugular foramen.

Somatic sensory:
- superior ganglion
- ear canal

Special sensory:
- inferior ganglion
- taste on posterior 1/3 tongue

Branchial motor:
- muscle from 3rd arch, stylopharyngeus

Visceral sensory:
- inferior ganglion
- pharynx, middle ear, carotid sinus/body, posterior 1/3 tongue

Visceral motor (parasymp):
- parotid gland

Front 29

Parasympathetic of IX

Back 29

Parasymp innevation to parotid gland.
Branch that carries the parasymp component = lesser petrosal nerve

Parasymp. nerves travel via tympanic branch (to middle ear), lesser petrosal nerve, to otic ganglion where it synapses, postganglionic fibers on V3 (auriculotemporal nerve).

Front 30

Gag Reflex

Back 30

Mucosa lining the pharynx is very sensitive to touch, CN IX

Causes contraction of the muscles (CN X, IX), "gagging"

Posterior 1/3 of tongue is in oropharynx, also very sensitive to touch.

Front 31

CN X - Vagus

Back 31

Exits via jugular foramen.

Somatic sensory:
- superior ganglion
- ear canal, dura of posterior fossa

Special sensory:
- inferior ganglion
- taste (base of tongue, epiglottis)

Branchial motor:
- muscles from 4th, 6th arches
- Muscles of pharynx, larynx, soft palate

Visceral sensory:
- inferior ganglion
- larynx, carotid sinus and body, thoracic and abdominal viscera

Visceral motor (parasymp):
- thoracic and abdominal viscera



Motor to muscles of pharynx, larynx and soft palate, except stylopharyngeus (IX) and tensor veli palatini (CN V3).

Recurrent laryngeal nerves:
- motor to laryngeal muscles (but not cricothyroid)
- sensory (from larynx below true cords)

External laryngeal nerve (from superior laryngeal nerve):
- motor to crycothyroid
- travels with superior thyroid artery

Internal laryngeal nerve (from superior laryngeal nerve):
- pierces the thyrohyoid membrane
- sensory to larynx above true cords

Front 32

Vagus Nerve: In the clinic

Back 32

Injury or compression to recurrent laryngeal nerve can cause horseness (if one cord paralyze) or loss of voice (both cords paralyzed).,

Injury to internal laryngeal nerve: loss of cough reflex.