Pharynx Week 5 FINISHED Flashcards
What is the pharynx and where is it located?
Part of the digestive system posterior to the nasal cavities, oral cavity and larynx. It also has respiratory function
Where does the pharynx extend? What does it lie against posteriorly?
Extends from the base of the skull to the inferior border of the cricoid cartilage (anteriorly) and the inferior border of C6 posteriorly
Posteriorly it lies against the prevertebral layer of the deep cervical fascia
What is the widest point of the pharynx and where is it?
The widest point ~ 5cm opposite the hyoid bone
What is the narrowest part of the pharynx and where is it?
Narrowest part ~1.5 cm at the inferior end of the pharynx where it is continuous with the oesophagus
What are the 3 regions of the pharynx?
nasopharynx - posterior to the nasal cavity and superior to the soft palate
oropharynx - posterior to the mouth and the oral cavity
laryngopharynx - posterior to the larynx
What is the nasopharynx and what is the function of the nasopharynx?
Respiratory function
Posterior extension of the nasal cavities
What are the 2 openings from the nasal cavity into the nasopharynx?
The nasal cavities open into the nasopharynx via the 2 choanae (paired openings)
What do the roof and the posterior surface of the nasopharynx form?
Roof and the posterior wall form a continuous surface that lie inferior to the body of the sphenoid and the basilar part of the occiput
What are the pharyngeal tonsils also known as?
Adenoids
Where are the pharyngeal tonsils/adenoids found?
Found in the roof and walls of the nasopharynx
Where are the tubal tonsils found?
Lymphoid tissue near the pharyngeal orifice of the pharyngotympanic tube
What is the function of the oropharynx?
Digestive function
What is superior to the oropharynx?
The soft palate
What is inferior to the oropharynx?
Base of the tongue and epiglottis
What is lateral to the oropharynx?
Laterally palatoglossal and palatopharyngeal arches
What are the palatine tonsils?
Lymphoid tissue found either side of the oropharynx
What is the laringopharynx and where is it found?
Hypopharynx
- Found between the superior border of the epiglottis
- To the inferior border of the cricoid cartilage where it becomes continuous with the oesophagus
- Posteriorly find the bodies of C4-6 vertebrae
What forms the laryngopharynx laterally and posteriorly?
Posteriorly and laterally formed by the middle and inferior constrictor muscles
What forms the internal surface of the laryngopharynx?
Internally the wall is formed by the palatopharyngeus and stylopharyngeus muscles
How does the laryngopharynx communicate with the larynx?
Communicates with the larynx via the laryngeal inlet
How many layers of muscle are in the wall of the pharynx?
2 layers
What is the orientation of the layers of muscle in the pharynx?
Externally circular
Internally longitudinal
How does the muscle orientation in the pharynx differ from other organs?
The pharynx has a muscle orientation external circular and internal longitudinal which is opposite to that of other organs e.g. the bladder
How many external constrictor muscles does the pharynx have? Are they voluntary or involuntary?
3
Involuntary
Describe the constrictor muscles in the pharynx. Where do they insert posteriorly?
3 curved sheets which lie on the posterior wall and sides of the pharynx.
Posteriorly they insert into the median fibrous raphe
Where do the constrictor muscles of the pharynx descend from and where do they go to?
They descends from the pharyngeal tubercle on the base of the skull to blend in with the oesophagus
What is the function of the pharyngeal muscles?
Contract sequentially superior to inferior
Propels food into the oesophagus
What is the nerve supply to the pharyngeal muscles?
Nerve supply:
- Pharyngeus plexus (Lies lateral wall of the pharynx mainly on the middle constrictor)
- IX & X and sympathetic from the superior cervical ganglion
Superior constrictor OIAN
Origin: Pterygoid hamulus (projection of the medial pterygoid plate) Pterygomandibular raphe (raphe = seam) (strand of tendinous fibres from the pterygoid hamulus to the posterior end of the mylohyoid line)
Insertion: Median raphe of pharynx, pharyngeal tubercle on the basilar part of the occipital bone
Innervation:
Pharyngeal branch of vagus and pharyngeal plexus
Action:
Constricts the wall of the pharynx during swallowing
Middle constrictor OIAN
Origin:
Stylohyoid ligament, horns of the hyoid bone
Insertion:
Median raphe of pharynx
Innervation:
Pharyngeal branch of vagus, pharyngeal plexus & branches of external & recurrent laryngeal nerves
Action:
Constricts the wall of the pharynx during swallowing
Inferior constrictor OIAN
Origin:
Oblique line of the thyroid cartilage, side of the cricoid cartilage
Insertion:
Median raphe of pharynx
Innervation:
Pharyngeal branch of vagus, pharyngeal plexus & branches of external & recurrent laryngeal nerves
Action:
Constricts the wall of the pharynx during swallowing
What are the 3 internal pharyngeal muscles?
Palatopharyngeus
Stylopharyngeus
Salpingopharyngeus
Palatopharyngeus OIAN
Origin:
Hard palate, palatine aponeurosis
Insertion:
Lateral wall of the pharynx, thyroid cartilage, oesophagus
Innervation:
Pharyngeal branch of vagus, pharyngeal plexus
Action:
Tenses the soft palate, Elevates (shorten and widens the pharynx and larynx during swallowing and speaking)
Salpingopharyngeus OIAN
Origin:
Cartilaginous part of the auditory tube
Insertion:
Blends with palatopharyngeus
Innervation:
Pharyngeal branch of vagus, pharyngeal plexus
Action:
Elevates (shorten and widens the pharynx and larynx during swallowing and speaking)
Stylopharyngeus OIAN
Origin:
Styloid process
Insertion:
Thyroid cartilage with palatopharyngeus
Innervation:
Glossopharyngeal (CN IX)
Action:
Elevates (shorten and widens the pharynx and larynx during swallowing and speaking)
What is the arterial supply of the pharynx?
Facial artery - tonsillar artery The ascending (facial) and descending (maxillary) palatine arteries Lingual artery (external carotid) Ascending pharyngeal artery (external carotid)
ALL BRANCHES OF THE EXTERNAL CAROTID ARTERY
What is the venous drainage of the pharynx?
External palatine vein —> internal jugular vein
What is the nerve supply of the pharynx?
Motor and sensory mainly from the pharyngeal plexus of nerves
Motor- vagus to all the mm of the pharynx except stylopharyngeus (CN IX G/P)
Sensory CN IX and CN V (2)
