Pharynx Flashcards
What is the pharynx?
Pharynx is a musculofascial cylinder that connects the nasal and oral cavities (head) to the larynx and oesophagus (neck)
What is the general function of the pharynx?
It is the common pathway for both food and air
What is the superior attachment of the pharynx?
Base of the skull
Inferiorly the pharynx is continuous with _____________ and _______________.
Larynx & Oesophagus
What are the attachments of the walls of the pharynx?
Nasal and oral cavities, and the larynx
What separates the pharynx from the vertebral bodies?
Retropharyngeal space (filled with loose connective tissue)
List the 3 divisions of the pharynx
Nasopharynx
Oropharynx
Laryngopharynx
Name the structures that open to each division of the pharynx respectively
Choanae open into nasopharynx
Oropharyngeal isthmus (posterior opening
of oral cavity) opens into oropharynx
Laryngeal inlet (superior aperture of larynx)
opens into laryngopharynx
Describe the roof of the nasopharynx
Formed by the sloping base of the skull, behind the choanae, above the level of the soft palate
What structure is found on the mucosa covering the roof of the nasopharynx? Describe this structure
Pharyngeal tonsil. I t is the collection of lymphoid tissue. It is called adenoids when enlarged.
What connects the middle ear to the nasopharynx?
Pharyngotympanic tube
Where does the pharyngeal opening of the pharyngotympanic tube lie?
Lies on the lateral wall of the nasopharynx, posterior to and slightly above the level of the hard palate
How does the pharyngotympanic tube enter the pharynx from the middle ear?
It extends forward, medially and downward from the middle ear to enter the nasopharynx
What are the two parts of the pharyngotympanic tube?
- Bony part (1/3rd proximal to middle ear)
- Cartilaginous part (2/3rd distal to middle ear)
What is the function of the pharyngotympanic tube?
Equalizes pressure on both sides of tympanic
membrane.
Where is the oropharynx situated?
It is situated behind the oral cavity, at the level of the soft palate to the superior margin of the epiglottis
What marks the boundary between the between the oral cavity and the oropharynx?
Palatoglossal arches
The opening between the palatoglossal arches is called _________________.
Oropharyngeal isthmus
Describe the anterior wall of the oropharynx
Inferior to the oropharyngeal isthmus, upper part of the posterior 1/3rd of the tongue
What structures are found on the anterior wall of the oropharynx?
Lingual tonsils
Explain where palatine tonsils are found
Lie on lateral walls
- On palatine fossa between palatoglossal and palatopharyngeal arches (just posterior to
oropharyngeal isthmus)
Where is the laryngopharynx situated?
From the superior margin of the epiglottis and the opening of the oesophagus (C6 vertebral level)
Inferior to the laryngeal inlet, what forms the anterior wall of the laryngopharynx?
Posterior wall of the larynx
What forms the pharyngeal wall?
Skeletal muscles and fascia
Gaps present between the skeletal muscles are reinforced by ______________.
Fascia
What are the two groups of pharyngeal muscles? Describe the fibre orientation of each group.
- Constrictor muscles
- Fibres oriented in circular direction - Longitudinal muscles
- Fibres oriented vertically
List the constrictor muscles (3)
- Superior constrictor muscles
- Middle constrictor muscles
- Inferior constrictor muscles
(named according to their position)
What are the anterior attachment points of constrictor muscles?
Lateral margins of bones, cartilages, and
ligaments of nasal cavity, oral cavity and larynx
What is the posterior attachment point of constrictor muscles?
Pharyngeal raphe
What is the innervation and action of the constrictor muscles
Innervation
* Vagus nerve
Action
* Together, muscles constrict pharyngeal cavity
During swallowing:
* Contract sequentially from superior to inferior to move a bolus of food down pharynx and into
oesophagus
List the longitudinal muscles (3)
- Stylopharyngeus muscle
- Salpingopharyngeus muscle
- Palatopharyngeus muscle
(named according to their origins)
Where do these longitudinal muscles attach/insert?
Descend from origin sites and attach onto
pharyngeal wall
What is the innervation and action of the longitudinal muscles?
Innervation
* Glossopharyngeal nerve: Stylopharyngeus muscle
* Vagus nerve: Salpingopharyngeus and
palatopharyngeus muscles
Action
* Elevate pharyngeal wall
* During swallowing: Pull pharyngeal wall up and
over bolus of food
What is the function of the fascia?
- Reinforces pharyngeal wall
- Separated into two layers which sandwich pharyngeal muscles between them
Name and describe each layer of fascia
- Buccopharyngeal fascia
- Thin layer
- Covers outside of muscular wall
- Component of pretracheal layer of cervical fascia - Pharyngobasilar fascia
- Much thicker layer
- Lines inner surface
What is the function of the gaps found between the muscles?
Provide important routes for muscles and
neurovascular structures
What transverses the gap superior to superior constrictor muscle?
- Levator veli palitini muscle
- Pharyngotympanic tube
What transverses the gap between superior and middle constrictor muscles (oropharyngeal triangle)?
- Stylopharyngeus muscle
- Glossopharyngeal nerve
What transverses the gap between middle and inferior constrictor muscles?
- Internal laryngeal nerve
- Internal laryngeal vessels
What transverses the gap inferior to the inferior constrictor muscle?
Recurrent laryngeal nerve
- Inferior laryngeal vessels
What is the blood supply for the upper parts of the pharynx?
Ascending pharyngeal artery
* Ascending palatine branch of facial artery
* Tonsilar branch of facial artery
* Numerous branches of maxillary and lingual arteries
(All arise from external carotid artery)
What is the blood supply for the lower parts of the pharynx?
Pharyngeal branches of inferior thyroid artery
Arises from thyrocervical trunk of subclavian artery
Describe the venous drainage of the pharynx.
Superiorly, the plexus formed by veins of the pharynx drain into the pterygoid plexus
Inferiorly, the plexus formed by the veins of the pharynx drain into facial and internal jugular veins.
Motor and most sensory innervation (excluding the nasopharynx) is provided by which nerves?
Branches of vagus and glossopharyngeal nerves
- Via pharyngeal plexus
Describe the pharyngeal plexus
Pharyngeal plexus:
- Pharyngeal branch of vagus nerve
- Pharyngeal branch of glossopharyngeal nerve
- Branches from external laryngeal nerve
What nerve provides motor innervation of all pharyngeal muscles
- Pharyngeal branch of vagus nerve via
pharyngeal plexus
T/F
The sylopharyngeus muscle is innervated by the vagus nerve.
F.
It is innervated by the glossopharyngeal nerve.
Name the nerve responsible for the sensory innervation of each part of the pharynx respectively
Nasopharynx:
- Pharyngeal branch of maxillary nerve
- Oropharynx:
- Pharyngeal branch of glossopharyngeal nerve
via pharyngeal plexus - Laryngopharynx:
- Internal laryngeal nerve
