10.2 Pharynx Flashcards
Where is the pharynx located?
Cranial Base to the
Inferior Border of the Cricoid Cartilage Anteriorly
Inferior Border of C6 Vertebra Posteriorly.
Where is the pharynx widest and narrowest?
Widest (Approximately 5cm) opposite the hyoid.
Narrowest (approximately 1.5cm) at its inferior end, where it is continuous with the oesophagus.
Borders, epithelium, function and contents of nasopharynx.
Posterior to nose, superior to the soft palate.
Pseudostratified ciliated columnar with goblet cells
Stratified squamous epithelium
Respiratory function - posterior extension of nasal cavities via chonae, conditioning inspired air and propagating to larynx.
Lymphoid tissue in Waldeyer’s ring
Adenoids
Eustachian tube orifice
Borders, vertebral level, epithelium, function and contents of oropharynx.
Soft palate to the superior border of the epiglottis.
C2/C3
Stratified squamous non-keratinised
Digestive
Voluntary and involuntary phase of swallowing.
Posterior 1/3 of tongue Lingual tonsils - Inferiorly to tongue Palatine tonsils Superior pharyngeal constrictor
Where are the palatine tonsils found?
Oropharynx between palatoglossal and palatopharyngela arches.
What is the blood supply to the palatine tonsils?
ECA - maxillary - facial - tonsillar
Pharyngeal venous plexus
What is the venous drainage of the palatine tonsils?
Jugulodigastric node
At angle of mandible
Enlarged in tonsilitis
Borders, vertebral level, epithelium, function and contents of laryngopharynx.
Superior border of the epiglottis –> Inferior border to cricoid cartilage.
Becomes continuous with oesophagus
Communicates with larynx via laryngeal inlet.
C3-C6
Stratified squamous non keratiniesed
Middle and inferior pharyngeal constrictors.
What forms the wall of the pharynx?
Outer circular muscle layer
Inner longitudinal muscle layer
Covered internally by pharyngobasilar fascia and mucous membrane.
What innervates the muscles of the pharynx?
Outer muscle layer and inner muscle layer innervated by CNX except stylopharyngeus (CNIX)
What forms the outer circular muscular layer, function, innervation?
Layers stacked like glasses - open anteriorly
Superior Constrictor
- Found in oropharynx
Middle Constrictor
- Found in the laryngopharynx
Inferior Constrictor
- Found in the larygopharynx
- Superior component (thyropharyngeus) has oblique fibres that attach to the thyroid cartilage.
- Lower horizontal fibres known as Cricopharyngeus that attach to the cricoid cartilage.
Contract sequentially from superior to inferior to constrict the lumen and propel the bolus of food into the oesophagus.
CNX
What are the two components of the inferior constrictor muscle?
Thyropharyngeus (oblique fibres to thyroid cartilage)
Cricopharyngeus (horizontal fibres to the cricoid cartilage)
Where does the outer muscular layer attach?
Posteriorly to the midline rap he
Incomplete anteriorly
Overlap inferior over superior.
What are the three muscles of the inner longitudinal layer?
Stylopharyngeus CNIX
Palatopharyngeus CNX
Salpingopharyngeus CNX
What do the inner longitudinal muscles do during swallowing?
Shorten and widen the pharynx
Salpingopharyngeus opens the Eustacian tube to equalise middle ear pressure.
Sensory innervation of pharynx
Nasopharynx - CNV1/CNV2
Oropharynx CNIX
LAryngopharynx - CNX
Vertebral levels of bony landamarks
C1 - Hard palate C2 - angle of mandible C3 - hyoid bone C4/C5 - thyroid cartilage C6 - cricoid cartilage
3 phases of swallowing
- Voluntary
- Pharyngeal
- Oesophageal
What occurs in voluntary phase
Tongue retracts, pushing bolus of food to oropharynx.
What occurs in pharyngeal phase
Pressure receptors in palate and pharynx stimulate swallow centre
Inhibition of breathing
Raising of larynx by supra hyoids (stabilised by infra hyoids)
Closure of glottis
Opening of upper oesophageal sphincter.
Contraction of pharyngeal constrictor muscles sequentially from the superior to inferior
What occurs in oesophageal phase?
Muscles in upper 1/3 = striated
Muscles in lower 2/3 = smooth involuntary
Peristalisis wave spreads along oesophagus propelling bolus down to stomach in 9 seconds.
Lower oesophageal sphincter opens.
Why does the thyroid elevate in swallowing?
Thyroid gland is attached to the hyoid bone so elevated with they laryngeal skeleton during swallowing. The inferior thyroid artery from the thyrocervical trunk is tortuous to allow extension when the thyroid moves up.
Blood supply to pharynx?
ECA - Maxillary - Facial
ECA - Lingual
ECA - Superior thyroid artery
ECA - Ascending pharyngeal
Venous drainage of pharynx?
Pharyngeal plexus - IJV
Afferent and efferent of gag reflex?
Stimulation of oropharynx
CNIX
CNX
Where are adenoids? When are they largest? When do they enlarge?
Lymphatic tissue collection
Found at junction of roof and posterior wall of nasopharynx
Largest from 3-8yo, regress
Enlarge with viral and bacterial URTI
Recurrent infection - chronically enlarged
Clinical features of nasal obstruction?
Mouth breathing Nasal speech Feeding difficulty Snoring / Obstructive sleep apnoea Chronic otitis media with effusion.
Risk of tonsillectomy?
Rutpure of tonsillar branch of facial artery
ICA or CNIX
What is quinsy? Treatment?
Peritonsillary abscess - infection spreads to peritonsillar tissue forming pus filled lesion.
Deviation of uvula - quinsy
Requires drainage and antibiotics
Common site for food to become stuck in pharynx?
Vallecula
Mucosa pouch bewteen tongue and epiglottis
Piriform fossa
Mucousal recess between central larynx and lateral lamina of thyroid cartilage
Describe pharyngeal pouch.
Inferior pharyngeal constrictor = thyropharyngeus and cricopharyngeus
In normal swallwoing, thyropharyngeus contracts as cricopharyngeus relaxes allowing propulsion of bolus into oesophagus without raising intrapharyngeal pressure.
If coordinated relaxation of cricopharyngeus does not occur, intrapharyngeal pressure rises, and mucosa forms a midline diverticulum where food can accumulate.
