Anatomy Presentation – Structures involved in swallowing
The hypopharynx is the lower portion of the pharynx. It is also known as the laryngopharynx.
There are three pharyngeal recesses: Food boluses can lodge in these recesses.
The vallecula is the space or depression between the base of the tongue and the epiglottis.
The two pyriform sinuses are located in the pharynx, beside the larynx. They are formed by the shape of muscle attachments to the pharyngeal walls.
The superior, middle, and inferior pharyngeal constrictor muscles make up the external circular layer of the pharynx.
The stylopharyngus m. and the salpingopharyngus m. make up the internal ...view middle of the document...
In the past, physicians frequently treated all types of swallowing problems by cutting the P.E. segment. This procedure is called myotomy.
The Glossopharyngeal Nerve (CN. IX)
It innervates the 3 salivary glands in the mouth. The saliva from these glands mixes with the chewed up food to form a bolus.
CN. IX has motor, sensory, and autonomic nervous system nerve fibers. It, along with the vagus (CN. X), provides some innervation to the upper pharyngeal constrictor muscles (Zemlin, 1997).
It innervates the stylopharyngeus muscle which elevates the larynx and pulls it forward during the pharyngeal stage of the swallow. This action also aids in the relaxation and opening of the cricopharyngeus muscle.
The glossopharyngeal nerve mediates all sensation, including taste, from the posterior 1/3 of the tongue.
CN. IX also carries sensation from the velum and the superior portion of the pharynx. A lesion may have impaired the gag reflex unilaterally (Zemlin, 1997).
The Vagus Nerve (CN. X)
The vagus is responsible for raising the velum as it innervates the glossopalatine and the levator veli palatine muscles.
The vagus along with CN. IX innervates the pharyngeal constrictor muscles.
The vagus along with CN. XI innervates the intrinsic musculature of the larynx. It is responsible for vocal fold adduction during the swallow.
The vagus also innervates the cricopharyngeus muscle.
The vagus controls the muscles involved in the esophageal stage of the swallow as well as those that control respiration. (This is the only cranial nerve that influences structures inferior to the neck.)
The vagus carries sensory information from the velum and posterior and inferior portions of the pharynx.
The vagus also mediates sensation in the larynx.
Swalloing vs Gagging
The Neuroanatomy of Swallowing
(Zemlin, 1997; Logemann, 1998, 1989; Morrell, 1984; Dobie, 1978)
In the past, the...