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==Introduction==

==Introduction==

The larynx is situated below where the [[Pharynx - Anatomy & Physiology|pharynx]] divides into the trachea and the [[Oesophagus - Anatomy & Physiology|oesophagus]]. It is contained partly within the rami of the mandible and extends caudally into the neck. '''Vocal folds''' and '''vestibular folds''' are present in the larynx and due to this, it is more commonly known as the voice box.

The larynx is situated below where the [[Pharynx - Anatomy & Physiology|pharynx]] divides into the trachea and the [[Oesophagus - Anatomy & Physiology|oesophagus]]. It is contained partly within the rami of the mandible and extends caudally into the neck. '''Vocal folds''' and '''vestibular folds''' are present in the larynx and due to this, it is more commonly known as the voice box.

The cartilageous larynx can be manually palpated in the living animal and is commonly implicated in respiratory conditions such as [[Diseases of the conducting airways#Laryngeal paralysis|roaring]].

The cartilageous larynx can be manually palpated in the living animal and is commonly implicated in respiratory conditions such as [[Diseases of the conducting airways#Laryngeal paralysis|roaring]].

==Structure==

==Structure==

===Epiglottis===

===Epiglottis===

The [[Epiglottis|epiglottis]] is the rostral margin of the larynx.

The [[Epiglottis|epiglottis]] is the rostral margin of the larynx. It is a flap of [[Bones and Cartilage - Anatomy & Physiology#Elastic Cartilage|elastic cartilage]] covered by mucous membrane. It forms the rostral boundary of the larynx and prevents food particles from entering the trachea. The epiglottis can return to its normal size and shape after distortion due to the vast amount of elastic fibres present within.

 

The epiglottis is a flap of [[Bones and Cartilage - Anatomy & Physiology#Elastic Cartilage|elastic cartilage]] covered by mucous membrane. It forms the rostral boundary of the [[Larynx - Anatomy & Physiology|larynx]] and prevents food particles from entering the trachea.

 

The epiglottis can return to its normal size and shape after distortion due to the vast amount of elastic fibres present within.

 

 

 

 

==The Cartilage of the Larynx==

==The Cartilage of the Larynx==

===Thyroid Cartilage===  

===Thyroid Cartilage===  

 

The thyroid cartilage is a [[Bones and Cartilage - Anatomy & Physiology#Hyaline Cartilage|hyaline cartilage]] and forms most of the floor of the larynx. The fusion of the two lateral plates varies in different species. The rostral part forms the 'Adam's apple'. The thyroid cartilage articulates with the '''thyrohyoid bone''' and the '''cricoid cartilage'''. It becomes brittle as the animal ages.

The thyroid cartilage is a [[Bones and Cartilage - Anatomy & Physiology#Hyaline Cartilage|hyaline cartilage]] and forms most of the floor of the larynx. The fusion of the two lateral plates varies in different species. The rostral part forms the 'Adam's apple'. The thyroid cartilage articulates with the '''thyrohyoid bone''' and the '''cricoid cartilage'''. It becomes brittle as the animal ages.

===Cricoid Cartilage===

===Cricoid Cartilage===

 

The cricoid cartilage is also a [[Bones and Cartilage - Anatomy & Physiology#Hyaline Cartilage|hyaline cartilage]]. It is signet ring shaped and is wider on the dorsal surface than the ventral surface. There is a crest on the midline of the dorsal surface and facets for '''arytenoid cartilages''' on the rostral edge. The cricoid cartilage articulates with the '''thyroid cartilage'''. It also becomes brittle as the animal ages.

The cricoid cartilage is also a [[Bones and Cartilage - Anatomy & Physiology#Hyaline Cartilage|hyaline cartilage]]. It is signet ring shaped and is wider on the dorsal surface than the ventral surface. There is a crest on the midline of the dorsal surface and facets for '''arytenoid cartilages''' on the rostral edge. The cricoid cartilage articulates with the '''thyroid cartilage'''. It also becomes brittle as the animal ages.

===Arytenoid Cartilage===

===Arytenoid Cartilage===

 

The arytenoid cartilage is also a [[Bones and Cartilage - Anatomy & Physiology#Hyaline Cartilage|hyaline cartilage]]. It is paired and articulates with the rostral part of the '''cricoid cartilage'''. A '''vocal process''' is present on the caudal surface where the vocal folds attach; a muscular process extends laterally and a corniculate process extends dorsomedially.

The arytenoid cartilage is also a [[Bones and Cartilage - Anatomy & Physiology#Hyaline Cartilage|hyaline cartilage]]. It is paired and articulates with the rostral part of the '''cricoid cartilage'''. A '''vocal process''' is present on the caudal surface where the vocal folds attach; a muscular process extends laterally and a corniculate process extends dorsomedially.

===Epiglottic Cartilage===

===Epiglottic Cartilage===

The epiglottic cartilage is an [[Bones and Cartilage - Anatomy & Physiology#Elastic Cartilage|elastic cartilage]], which is the most flexible and most rostral type of cartilage. The thinner stalk-like part, is attached to the root of the [[Tongue - Anatomy & Physiology|tongue]], the body of the '''thyroid cartilage''' and the '''basihyoid bone'''. The larger blade-like part lies behind the soft palate and points dorso-rostrally. During [[Deglutition|deglutition]], the large blade part of the '''epiglottic cartilage''' partially covers the entrance to the trachea.

The epiglottic cartilage is an [[Bones and Cartilage - Anatomy & Physiology#Elastic Cartilage|elastic cartilage]], which is the most flexible and most rostral type of cartilage. The thinner stalk-like part, is attached to the root of the [[Tongue - Anatomy & Physiology|tongue]], the body of the '''thyroid cartilage''' and the '''basihyoid bone'''. The larger blade-like part lies behind the soft palate and points dorso-rostrally. During [[Deglutition|deglutition]], the large blade part of the '''epiglottic cartilage''' partially covers the entrance to the trachea.

===Transverse arytenoid muscle===

===Transverse arytenoid muscle===

The transverse arytenoid muscle is innervated by the '''caudal laryngeal nerve''', a branch of the vagus nerve ([[Cranial Nerves - Anatomy & Physiology|CN X]]). It completes the '''muscular sphincter arrangment''' and spans the '''arytenoid cartilages'''.

The transverse arytenoid muscle is innervated by the '''caudal laryngeal nerve''', a branch of the vagus nerve ([[Cranial Nerves - Anatomy & Physiology|CN X]]). It completes the '''muscular sphincter arrangment''' and spans the '''arytenoid cartilages'''.

==Laryngeal Pharynx==

==Laryngeal Pharynx==

Mucous glands are present in the larynx with a particularly high density in the ventricles. '''Stratified squamous epithelium''' is located rostrally around the laryngeal entrance, whilst '''ciliated pseudostratified columnar epithelium''' is elsewhere.

Mucous glands are present in the larynx with a particularly high density in the ventricles. '''Stratified squamous epithelium''' is located rostrally around the laryngeal entrance, whilst '''ciliated pseudostratified columnar epithelium''' is elsewhere.

See [[Bones and Cartilage - Anatomy & Physiology#Elastic Cartilage|elastic cartilage histology]] for more information.

See [[Bones and Cartilage - Anatomy & Physiology#Elastic Cartilage|elastic cartilage histology]] for more information.