Anatomy - The External Pharynx and Larynx Flashcards
What type of tissue loosely covers the 3 constrictor muscles of the pharynx?
Loose areolar tissue
What is the origin of the superior constrictor muscle?
The medial pterygoid and pterygomandibular raphe (mandibular)
What is the origin of the middle constrictor muscle?
The hyoid bone and stylohyoid ligament
What is the origin of the inferior constrictor muscle?
Thyrophayngeus and Cricophayngeus Muscles
Which cranial nerves form the pharyngeal plexus found at the posterior of the pharynx?
Vagus (CN X) and Glossopharyngeal (CN IX)
What is Killian’s dehiscence?
The weakest part of the pharyngeal wall Between diverging fibres of the inferior constrictor muscle
Describe the sympathetic chain found in the neck
- 3 ganglia:
- Superior cervical ganglion: prominent, just below the skull
- Middle cervical ganglion: smaller
- Inferior cervical ganglion: often fused with first thoracic ganglion to form the stellate ganglion
From which cranial nerve does the superior laryngeal nerve branch off? What 2 branches does it give off itself?
Vagus nerves 2 Branches: internal laryngeal nerve (sensation to larynx above vocal cords) and external laryngeal nerve (supplies cricothyroid and cricopharyngeus muscles of the inferior constrictor muscle)
What 2 arteries does the common carotid artery bifurcate into?
external and internal carotid artery
What is found at the origin of the internal carotid artery? How is it innervated?
carotid sinus (visible swelling) innervated by glossopharyngeal nerve (CN IX)
What does the glossopharyngeal nerve supply?
Sensory: Innervates the oropharynx, carotid body and sinus, posterior 1/3 of the tongue, middle ear cavity and Eustachian tube. Special sensory: Provides taste sensation to the posterior 1/3 of the tongue. Parasympathetic: Provides parasympathetic innervation to the parotid gland. Motor: Innervates the stylopharyngeus muscle of the pharynx.
What forms the ganglia on the sympathetic chains and vagus nerves?
A collection of neuron cell bodies
What is the name of the fused first thoracic and lower cervical sympathetic ganglia?
The stellate ganglion
What structures are supplied by the superior laryngeal nerve?
Sensation to the inside of the larynx down to the vocal cords and the cricothyroid muscle
Which special sensation is carried in the glossopharyngeal nerve?
Taste from the posterior 1/3 of the tongue.
What is the location of the carotid sinus and what sense does it detect?
The origin of the internal carotid artery; blood pressure.
Which structures lie immediately behind the pharyngeal wall?
A thin layer of loose areolar tissue and then the cervical vertebral bodies
Which parts of the pharynx lie below the lower border of the mandible?
The hypopharynx is also known as laryngopharynx
Where does the external pharynx begin and end?
- at the base of the skull
- the inferior border of the cricoid cartilage (C6)
What are the boundaries of the nasopharynx?
- the base of the skull and the soft palate
- continuous with the nasal cavity
What is found in the posterior superior nasopharynx area?
adenoid tonsils
Describe the histology of the nasopharynx?
- respiratory endothelium
- Ciliated pseudo-stratified columnar epithelium with goblet cells
What the 4 structures found within the oropharynx?
- Posterior one third of the tongue
- lingual tonsils - lymphoid tissue at the base of the tongue
- Palatine tonsils - lymphoid tissue located in the tonsillar fossa (between the palatoglossal and Palatino pharyngeal arches of the oral cavity)
What does Waldeyer’s Ring consist of?
A ring of lymphoid tissue in the nasal and oral pharynx formed by the paired Palatine tonsils, adenoid tonsils and lingual tonsils
What is the function of the Oropharynx?
The voluntary and in voluntary phases of swallowing
Describe the borders of the laryngopharynx?
- Superior border of the epiglottis and inferior border of the cricoid cartilage (C6)
- Continuous with the oesophagus
The muscles of the pharynx are mostly innovated by which nerve? What is the only exception?
- All innovated by the vagus nerve
- except the stylopharyngeus muscle
- Innovated by the Glossopharyngeal nerve
Name the three circular pharyngeal constrictor muscles? How are they innervated?
- the superior, middle and inferior pharyngeal constructors
- All innovated by the vagus nerve
- Stacked like glasses forming an incomplete muscular circle attaching anteriorly to the structures in the neck
Describe the superior pharyngeal constrictor muscle?
- located in the oropharynx
- Originates from the medial pterygoid plate and pterygomandibular raphe
- Inserts posteriorly to the pharyngeal tubercle of the occiput and medial pharyngeal raphe
Describe the middle pharyngeal constrictor muscle?
- located in the laryngopharynx
- Originates from the styohyoid Ligament and horns of the hyoid bone
- Inserts posteriorly to the pharyngeal raphe
Describe the inferior pharyngeal constructor muscle?
- located in the laryngopharynx
- Has two components:
- superior component (thyropharyngeus) has oblique fibres that attach to the thyroid cartilage
- The inferior component (cricopharyngeus) has horizontal fibres that attach to the cricoid cartilage
Describe the inner aspect of the constrictor muscles?
- Lined by thick pharynogobasilar fascia
- Attached to pharyngeal tubercle - the auditory (eustachian) tube and medial pterygoid plate
- Fascia bridges the gap between the constrictor muscles and the base of the skull
Name the three longitudinal muscles? What is their function?
- The stylopharyngeus, palatopharyngeus and salpingopharyngeus
- Actor shorten and widen the pharynx and elevate the larynx during swallowing
Describe the stylopharyngeus Muscle?
- arises from the styloid process of the temporal bone
- Inserts into the pharynx
- innovated by the glossopharyngeal nerve
Describe the palatopharyngeus Muscle?
- Arises from the hard palate of the oral cavity
- inserts into the pharynx
- innovated by vagus nerve
Describe the salpingopharyngeus Muscle?
- arises from the eustachian tube
- Inserts into the pharynx
- innovated by the vagus nerve
- also opens the eustachian tube to equalise the pressure in the middle ear
Describe the motor and sensory innovation of the majority of the pharynx? What is the exception?
- Pharyngeal plexus
- except for the nasopharynx
What is the pharyngeal plexus made up and where is its location?
- overlies the middle pharyngeal constructor muscle
- pharyngeal branches from the glossopharyngeal nerve (CN 9)
- pharyngeal branches from the vagus nerve (CV 10)
- branches from the external laryngeal nerve
- sympathetic fibres from the superior cervical ganglion
From which branch does the pharynx receive sensory innovation? What is the exception?
- Glossopharyngeal nerve
- Anterior and superior aspect of nasopharynx is innovated by the maxillary nerve
- inferior aspect of the laryngopharynx is innovated by the internal branch the vagus nerve
All muscles of the pharynx are innovated by which nerve? What is the exception?
- Vagus nerve
- except the stylopharyngeus Longitudinal muscle which is innovated by the glossopharyngeal nerve
Arterial supply to the pharynx is by the branches of which artery?
- external carotid artery
- ascending pharyngeal artery
- Branches of the facial artery
- branches of the lingual and maxillary arteries
Name the swelling of the internal carotid artery? What occurs here and how is it innovated?
- Carotid sinus
- the origin of the internal carotid artery (where the common carotid artery bifurcates)
- Innovated by the glossopharyngeal nerve
Describe Venous drainage of the pharynx?
via the pharyngeal venous plexus which drains into the internal jugular vein
Describe the journey of the vagus nerve in the neck and its relation to the superior laryngeal nerve?
- vagus nerve is in the carotid sheath
- sensory ganglia just before entering the skull ( gets wider)
- branches at the top of the neck to form the superior laryngeal nerve
- passes over the carotid artery
- disappears between the gap between the middle and inferior constrictor muscles
Describe how the superior laryngeal nerve branches?
- branches to form the internal laryngeal nerve
- sensory nerve to the larynx above the vocal cords
- external laryngeal nerve
- supplies the crico-thyroid muscle and the crico-pharyngeus part of the inferior constructor muscle
Describe the journey of the hypoglossal nerve?
- between the internal carotid artery and the mandible
- lateral to the carotid sheath
- curves forward 90 degrees and disappears under the tongue
What is the clinical relevance of the carotid sinus?
- measures blood pressure
- pressure on the carotid sinus can fall the sensory receptors into thinking the blood pressure is too high
- sensory signals are sent to the brain by the glossopharyngeal nerve
- in a return signal through the vagus nerve to slow the heart rate
- it can be used on patients with a certain fast heart rate
What can happen if the stroke causes Sensation loss from the glossopharyngeal nerve?
- When they swallow they can’t detect any fluid passing into the pharynx
- Leads the fluid entering the lungs
- Can cause infection
What structures like immediately behind the pharyngeal wall?
- thin layer of loose areola tissue then the cervical vertebrae bodies
