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ANA534 Pharynx
learning objective answers to pharynx
Question | Answer |
---|---|
Between which two fascial layers is the retropharyngeal space located? | Between the pretracheal fascia anteriorly and the prevertbral fascia posteriorly. |
What fills the retropharyngeal space? | Loose areolar connective tissue - the buccopharyngeal fascia |
Where is the “danger space” located? | Between the anterior and posterior components of the prevertebral space. |
What are the inferior relationships of the retropharyngeal and danger spaces? | They both extend down into the posterior mediastinuim of the thorax. |
Why are the retropharyngeal and danger spaces clinically important? | They both extend down into the posterior mediastinuim of the thorax. |
What is unusual about the construction of the pharynx? | The pharynx essentially has an “open” anterior wall that is composed of three differing visceral regions. |
What regions/structures communicate with the pharynx in it’s anterior aspect (in order from superior to inferior)? | The nasal cavity via the posterior choanae, the oral cavity via the oral isthmus, and the larynx via the laryngeal inlet. |
List the muscles that comprise the pharyngeal wall and their general anterior attachments. | The superior constrictor that attaches to the pterygomandibular raphe; the middle constrictor that attaches to the stylohyoid ligament and the hyoid bone; and the inferior constrictor that attaches to the thyroid and cricoid cartilages of the larynx. |
Which of the pharyngeal constrictors attaches posteriorly to the pharyngeal tubercle? | The superior constrictor |
What spans the gap between the superior constrictor and the base of the skull laterally? | The pharyngobasilar membrane/fascia. |
Name one large, important structure that pierces the fascia membrane that connects the superior constrictor and the base of the skull laterally. | The auditory tube. |
Name two important structures that pass between the overlapping edges of the superior and middle constrictors. | The stylopharnygeus muscles and glossopharyngeal nerve (CN IX). |
Identify a common midline structure into which all three pharyngeal constrictors attach posteriorly. | The pharyngeal (midline) raphe which in turn attaches superiorly to the pharyngeal tubercle. |
Identify another muscle that arises from the pterygomandibular raphe, but from its anterior aspect. State it’s specific innervation. | The buccinator m.; buccal branch of CN VII. |
State the innervation of all three pharyngeal constrictors. | The pharyngeal plexus (XI via X). |
What comprises the pharyngeal plexus? | CN IX; CN X and fibers from the sympathetic trunk form the pharyngeal plexus. |
State a rule of thumb for motor innervation of pharyngeal muscles. | The vagus nerve (CN X) is motor to all the muscles of the pharynx (via the pharyngeal plexus) except the stylopharyngeus which receives its motor innervation by the glossopharyngeal (CN IX). |
Which specific nerve supplies sensory innervation to the pharynx? | The glossopharyngeal nerve (CN IX) |
Which two nerves are involved in the gag reflex. | The glossopharyngeal (CN IX) and the vagus (CN X). |
Which of these two nerves initiates the gag reflex. | The glossopharyngeal since it is sensory. The sensation triggers the reflex at which time the vagus stimulates the motor innervation of the pharyngeal muscles. |
What are the 3 divisions of the pharynx and the communications (things that open into) in each region? | Nasopharynx (posterior choanae of nasal cavity); oropharynx (oral cavity through the posterior arch); laryngopharynx (larynx). |
Define the boundaries of each subregion of the pharynx. | nasopharynx- posterior choanae to the superior border of the soft palate oropharynx -soft palate to the superior border of the epiglottis laryngopharynx- upper border of the epiglottis to the lower border of the cricoid cartilage. |
What is the function of the pharyngeal constrictors? | The pharyngeal constrictors constrict the pharynx forcing the bolus of food towards the esophagus during the act of swallowing. |
What muscle joins the salpingopharyngeus prior to its fusing into the pharyngeal wall? | The palatopharyngeus. |
What is the generalized function of the palatopharyngeus, salpingopharyngeus, and stylopharyngeus mm.? | They all functioning in elevating the pharynx and larynx during swallowing and speaking. |
State the innervation of the palatopharyngeus | pharyngeal plexus |
State the innervation of the salpingopharyngeus | pharyngeal plexus |
State the innervation of the stylopharyngeus | glossopharyngeal nerve (CN IX). |
What keep food from entering the larynx after passing through the oropharynx and down into the laryngopharynx on its way to the esophagus? | The epiglottis is made of elastic cartilage and folds down over the opening to the larynx during swallowing prevent food and/or water from entering the larynx. If some does, it triggers the cough reflex to expel the food from the airway. |