Canine Head - Pharynx/Larynx

Pharynx

• A common passageway to both the respiratory and digestive systems

• Connects nasal and oral cavities

What two cavities does the pharynx connect?

Nasal and oral cavities

The three divisions of the pharynx

1. Nasopharynx

2. Oropharynx

3. Laryngopharynx

Arches of the pharynx

• Palatoglossal arch

• Palatopharyngeal arch

Pharyngeal opening of the auditory tube; it’s the reason why your ears pop when there’s high pressure

Nasopharynx

Two important parts of the laryngopharynx

1. Piriform recess

2. Pharyngoesophageal limen

Potential space for foreign body entrapment in the laryngopharynx

Piriform recess

What is the structure that is an annual constriction of mucosa that indicates a division between the laryngopharynx and the esophagus?

Pharyngoesophageal limen

Palatoglossal arch

Connection between tongue and soft palate; associated with oral cavity/oropharynx

Palatopharyngeal arch

Demarcates separation between the nasopharynx and laryngopharynx

Larynx

Musculocartilaginous organ whose cartilages interconnects together that are rostral to the trachea. It is a respiratory passage way into trachea

What does the larynx do?

• Aids in vocalization

• prevents inspiration of foreign materials

What suspends the larynx?

hyoid apparatus

What are the four laryngeal cartilages?

1. Epiglottis

2. Thyroid

3. Arytenoid

4. Cricoid

Important feature of the epiglottis

Aryepiglottic fold

Aryepiglottic fold

Connection between the epiglottis and arytenoid cartilage

What are two anatomical features of the larynx that have to do with vocal folds?

• (Lateral) Laryngeal ventricle

• Glottis

What is the caudal border of the (lateral) laryngeal ventricle?

Vocal fold

What is the rostral border of the (lateral) laryngeal ventricle?

Vestibular fold

What is the “voice box” of the larynx that is responsible for an animal producing vocalizations/noise?

Glottis

How does the glottis make an animal produce noise?

The vocal folds of the glottis vibrates in the wind/air, which produces sound

What feature is the opening into the glottis?

Rima glottidis

Dorsal part of the rima glottidis

Corniculate process arytenoid

What is the ventral part of hte rima glottidis?

Epiglottis

What are the ligaments of the larynx?

• Cricothyroid

• Cricotracheal

Which ligament of the larynx is most rostral?

Cricothyroid

Which ligament of the larynx is most caudal?

Cricotracheal

Describe the passageway of air into the body when breathing

Air → nasal cavity → choanae → nasopharynx → intrapharyngeal ostium → larynx → cricoid cartilage → trachea

Describe the passageway of food into the body

Food → oral cavity → isthmus of fauces → oropharynx → laryngopharynx → esophagus

How does food that you are eating go into the esophagus instead of the trachea?

The bolus of food pushes on the epiglottis of the larynx, which forces the opening of the larynx (rema glossitis) shut, allowing food to slide dorsally into the laryngopharynx and the into the esophagus.