The Pharynx Flashcards
What are the three divisions of the pharynx?
nasopharynx (at back of nasal cavity)
oropharynx (at back of oral cavity)
laryngopharynx (behind larynx)
What is the pharynx?
The pharynx is a tube made up of skeletal muscle, fascia, and mucosa, that transports air to the laryngeal inlet and food to the digestive inlet (oesophagus)
It extends from the skull base to cricoid cartilage (vertebral level c6), before it becomes oesophagus.
The nasopharynx is the superior aspect of the pharynx, what are the boundaries of the nasopharynx?
Roof: base of skull
Floor: soft palate
Anterior: nasal choanae
Lateral and posterior: superior constrictor muscle with overlying mucosa
Mostly sits at the back of the nose, extending from the nasal cavity to the top of the soft palate. The nasopharynx is bound by the superior constrictor muscle.
What is the function of the nasopharynx
The function of the nasopharynx is to transmit air to the laryngeal inlet to aid breathing and speaking.
Equalises pressure in the middle ear by opening and closing the eustachian tube. (auditory tubes).
Pharyngeal tonsils/adenoids on are located in the roof and posterior wall of the nasopharynx.
What are the boundaries of the oropharynx?
Oropharynx continues inferiorly from the soft palate to the epiglottis. Largely bound by middle constrictor muscle.
Superior: soft palate
Inferior: tip of epiglottis
Lateral and posterior: superior and middle constrictor muscles
Anterior: tongue base and palatoglossal folds
What structures are found in the oropharynx?
Palatine tonsils- tonsils you can see (tonsilitis)
Valleculae- the groove at the base of the tongue. Prevent saliva and debris from entering the laryngeal inlet.
Lingual tonsils- tonsils in the posterior 1/3 of tongue
The laryngopharynx extends inferiorly from the valleculae to the cricoid cartilage at level C6. What are the boundaries of the laryngopharynx.
Superior: tip of epiglottis (or level of hyoid bone)
Inferior: inferior margin of cricoid cartilage
Lateral and posterior: middle and inferior constrictor muscles
Anterior: larynx
Function of the laryngopharynx
Involved in final stage of swallowing. Powerful contraction of the pharyngeal constrictor
What features are present in the laryngopharynx?
Killian’s dehiscence- weak point between thyropharyngeus and cricopharyngeus
Piriform recesses
What are the pharyngeal constrictor muscles?
Three pharyngeal constrictor muscles:
Superior constrictor- uppermost pharyngeal constrictor, located in the oropharynx.
Attachments=
- Skull (base of skull and pterygoid hamulus)
- Pterygomandibular raphe (ligament between medial pterygoid plate and mandible)
- Inside of mandible (mylohyoid line)
Middle constrictor- located in the laryngopharynx. Originates from the stylohyoid ligament and the horns of the hyoid bone
Inferior constrictor- comprised of thyropharyngeus (arises from thyroid cartilage) and the cricopharyngeus (arises from cricoid cartilage). This area between the two is a weak area in the mucosa.
The constrictor muscles create a muscular tube for the passage of food/air
All pharyngeal constrictor muscles insert posteriorly to the pharyngeal raphe.
What can the Killians dehiscence (weak part between the thyropharyngeus and the cricopharyngeus) result in?
Can outpouch to create pharyngeal pouch/ Zenker’s diverticulum.
Dysphagia.
Regurgitation of undigested food that goes into pouch.
Gurgling noises when swallowing.
Neck swelling
Recurrent cough.
Which cranial nerves innervates the pharyngeal muscles?
Motor innervation:
Pharyngeal branches from the glossopharyngeal nerve (CN IX) innervates the stylopharyngeus
Pharyngeal branch of the vagus nerve (CN X).
Sensory innervation:
Oropharynx= CN IX (glossopharyngeal)
Area around laryngeal inlet/ laryngopharynx= CNX (vagus)
Soft palate and pharyngeal roof, nasopharynx= V2 (maxillary division of trigeminal)
What are the longitudinal pharyngeal muscles?
Stylopharyngeus- originates from the styloid process of the temporal bone and inserts onto the internal aspect of the pharynx by passing through the gap between the superior and middle constrictor. Motor innervation by glossopharyngeal nerve (CN IX)
Palatopharyngeus- originates from the soft palate and inserts into internal aspect of pharynx. Motor innervation by the pharyngeal branch of the vagus nerve (CN X)
Salpingopharyngeus- originates from the inferior aspect of Eustachian tube and inserts onto the internal aspect of the pharynx. Contraction opens the eustachian tube to equalise pressure. Innervated by the vagus nerve (CN X)
What is the function of the pharyngeal muscles?
Act to elevate pharyngeal wall during swallowing.
Opens the auditory tube (salpingopharyngeus)
What is the Waldeyer’s ring of lymphoid tissue?
ringed arangement in the naso- oropharynx formed by tonsils.
Palatine tonsils (between palatoglossus and palatopharyngeus)
Pharyngeal tonsils (aka adenoids, roof of pharynx)
Lingual tonsils (behind terminal sulcus/ in posterior 1/3 of tongue)
Tubal
