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Equine Upper Respiratory Tract - Horse Anatomy (view source)
Revision as of 21:56, 15 November 2012
, 21:56, 15 November 2012→Larynx
====Thyroarytenoid muscle (''thyroarytenoideus'')====
====Thyroarytenoid muscle (''thyroarytenoideus'')====
The thyroarytenoid muscle is innervated by the '''caudal laryngeal nerve''', a branch of the vagus nerve ([[Cranial Nerves - Anatomy & Physiology|CN X]]). It runs from the laryngeal floor to the '''thyroid cartilage''' and '''arytenoid cartilage''' and alters the tension of the vocal and vestibular folds. It forms part of the '''sphincter muscular arrangement'''.
The thyroarytenoid muscle is innervated by the '''caudal laryngeal nerve''', a branch of the vagus nerve ([[Cranial Nerves - Anatomy & Physiology|CN X]]). It runs from the laryngeal floor to the '''thyroid cartilage''' and '''arytenoid cartilage''' and alters the tension of the vocal and vestibular folds. It forms part of the '''sphincter muscular arrangement'''. In the horse, it is divided into 2 parts; the rostral and caudal vocalis, which are situated within the vocal folds and vestibular folds.
====Transverse arytenoid muscle (''arytenoideus transversus'')====
====Transverse arytenoid muscle (''arytenoideus transversus'')====
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==
The laryngeal pharynx is the largest part of the [[Pharynx - Anatomy & Physiology|pharynx]]. It is wide rostrally and narrows caudally. The laryngeal pharynx joins the [[Oesophagus - Anatomy & Physiology|oesophagus]] at the mucosal folds. The lumen is closed at rest by the roof and walls falling towards the floor. The floor of the laryngeal pharynx contains the opening into the larynx - epiglottis, arytenoid cartilages and the aryepiglottic folds.
==Function==
The larynx protects the trachea in [[Deglutition|swallowing]], preventing aspiration of foreign material. During swallowing, the larynx is moved rostrally causing the epiglottis to partially cover the laryngeal entrance. Solid foods are carried over the laryngeal entrance by the muscles of the [[Pharynx - Anatomy & Physiology|pharynx]]. Fluids are deflected by the epiglottis. Closure of the glottis also prevents food passing down the larynx. The reflex stimulation of the mucosa promotes the coughing reflex.
The larynx also allows the passage of air to the lungs and increases the intra-abdominal pressure. The glottis can widen by adduction of the vocal folds when breathing is vigorous. In addition to this, the larynx is used for vocalisation.
==Vasculature==
'''Laryngeal branch of the superior thyroid artery''' supplies the rostral larynx and is a branch of the '''carotid artery'''.
'''Laryngeal branch of inferior thyroid artery''' supplies the caudal larynx and is branching from the '''subclavian artery''' from the '''thyrocervical trunk'''.
'''Laryngeal branch of cricothyroid artery''' branches from the '''superior thyroid artery'''.
==Innervation==
The larynx is innervated by branches of the '''vagus nerve''' ([[Cranial Nerves - Anatomy & Physiology|CN X]]).
'''Cranial laryngeal nerve''' has two branches. The internal branch innervates the mucosa and the external branch innervates the '''cricothyroid muscle''' and constricts the [[Pharynx - Anatomy & Physiology|pharynx]].
'''Caudal (recurrent) laryngeal nerve''' innervates the intrinsic muscles of the larynx (except the cricothyroid muscle).
==Pharynx==
==Pharynx==