Pharynx and Larynx Flashcards
Describe the anatomical relationships: Anterior to the pharynx
- Opening into nasal cavity
- Soft palate
- Opening into oral cavity & posterior surface of tongue
- Opening into larynx
- Posterior surface of larynx
Describe the anatomical relationships: Posterior to the pharynx
- Buccopharyngeal part of visceral layer of deep cervical fascia
- Retropharyngeal space
- Prevertebral fascia
- C1-C6 vertebrae: anterior arch of atlas, vertebral bodies C2-C6
Describe the anatomical relationships: Postero-lateral to the pharynx
- Internal jugular vein, internal carotid artery
* Sympathetic trunk, CN IX, X, XI, XII
Name the pharyngeal constrictor muscles and where they originate/attach
• Superior pharyngeal constrictor
o Main origin: pterygomandibular raphe & adjacent bone on the mandible & pterygoid hamulus
• Middle pharyngeal constrictor
o Main origin: Upper margin of greater horn of the hyoid bone
• Inferior pharyngeal constrictor
o Main origin: Cricoid cartilage, tendinous arch etc
o The inferior pharyngeal constrictor muscle includes the cricopharyngeus forms → upper oesophageal sphincter
Name the elevators of the pharynx, and their INNERVATION
Palatopharyngeus = CNX
Stylopharyngeus == CNIX
Salpingopharyngeus = CNX
What is in the Nasopharynx?
What makes the roof of the nasopharynx
- Roof: Occipital & sphenoid bones
- Tonsil on roof = pharyngeal tonsil (adenoids when enlarged)
• Opening of the eustachian tube (pharyngotympanic tube, auditory tube)
o Other end of tube: middle ear (tympanic cavity)
o Allows equalization of pressure across the tympanic membrane
o Note: potential spread of infection from the nasal cavity to the middle ear → otitis media
What is in the oropharynx?
• Palatoglossal & palatopharyngeal arches & muscles
o Palatine tonsil lies between these two arches
• The posterior 1/3 of tongue is in the oropharynx
o Contains lingual tonsils
• Superior & middle constrictors, with stylopharyngeus & CN IX between them
CN IX: somatosensation & taste on posterior 1/3 tongue
What does CNIX run between and what is its function?
• Superior & middle constrictors, with stylopharyngeus & CN IX between them
CN IX: somatosensation & taste on posterior 1/3 tongue
What is in the laryngopharynx?
What holes may food lodge in?
• Inferior pharyngeal constrictor
• Small swallowed objects (food) may lodge in…
o Valleculae – between epiglottis & tongue
o Piriform recess – posteriorly between cricoid & thyroid cartilages
• In the flood of the recess, under the mucous membrane = internal laryngeal nerve → potential damage if something sharp lodges in the piriform recess
What is the lymphatics in the pharynx?
- Tonsils: lymphoid aggregations in mucosa of pharynx → lingual, palatine, pharyngeal
- Lymphatic drainage → retropharyngeal nodes → deep cervical nodes along IJV (within carotid sheath – collect most lymph from the head & neck)
What is the blood supply of the pharynx?
o From inferior thyroid artery - from thyrocervical trunk
o From superior thyroid, ascending pharyngeal, lingual, facial, maxillary arteries –> all from external carotid artery
Describe the innervation of muscles of the pharynx
Where are the LMN’s located
• All are supplied by the vagus (CN X), except stylopharyngeus by glossopharyngeal (CN IX)
- All LMNs of IX & X are in the nucleus ambiguus (rostral medulla, posterior to the inferior olivary nucleus)
- CN IX, X exit brainstem at the posterior olivary sulcus
- Exit the skull via the jugular foramen
Describe what would happen if there was a LMN lesion to CNX
ipsilateral paralysis - ie. dysphagia- difficulty swallowing
If there is an UMN lesion
There would be no problems due to the nature of the CBT
What is the SENSORY innervation of the pharynx
• CNV2 (maxillary), IX, X → primary neurons in the trigeminal, petrosal & nodose ganglion
• Conscious sensory processing
o Same as for sensation from face – 2nd order neurons in main & descending nuclei of V
o → TTT → VPM → primary SSC
Describe the gag reflex
Afferent mainly CNIX, also X, V -> descending nucleus of V, nucleus ambiguus -> CNX and IX
Describe the glossopharyngeal nerve-
where does it run?
What are its functions?
• Close to stylopharyngeus (supplies it), between external & internal carotid arteries
o Sensory (general & taste) to posterior 1/3 of tongue
o Sensory to much of pharynx
o Sensory – carotid sinus & body (baro & chemoreceptors)
o Parasympathetic to parotid (different pathway)
• Inferior salivatory nucleus, come out of CN IX- > inferior petrosal nerve -> synapse in Otic ganglion & travel with V3 branches to the parotid gland
What nerves are used in the action of SWALLOWING?
CNX, Facial and V3
Tongue moves food bolus posteriorly
CNVII
Soft palate elevated to close off nasopharynx
CNX - palatoglossus, palatopharyngeus, levator tensor palitini
CNV3- tensor veli palatine
Larynx elevated & moved anteriorly by suprahyoids & thyrohyoid, which opens laryngopharynx
CNV3: Suprahyoid: mylohyoid, anterior belly of digastric
CNVII: Stylohyoid,
C1 (travels with CNXII) geniohyoid
Wave of relaxation & contraction of pharyngeal constrictors from above downwards
CNX
Laryngeal inlet narrowed, epiglottis pulled posteriorly
CNX
Upper oesophageal sphincter relaxes to allow food into oesophagus, then relaxes
CNX
What is the larynx part of?
Conducting zone (not respiratory as this means gas exchange) Lower respiratory tract
Functions of the larynx
- Conduit for air from the URT to LRT
- Prevents food & liquid from entering the LRT when swallowing
- Voice production (phonation)
Anatomical relationships
- Hyoid bone – superior
- Infrahyoid muscles – anterolateral
- Thyroid gland – inferior, lateral
- Trachea – inferior
- Laryngopharynx, buccopharyngeal fascia, retropharyngeal space, vertebral bodies C3/4 – C6 – Posterior
What are the unpaired cartilages of the larynx?
Thyroid cricoid epiglottic
What are the paired cartilages of the larynx
Arytenoid, corniculate, cuneiform
What is the innervation of the muscles of the larynx?
All by vagus nerve (CNX)
- Most via the recurrent laryngeal nerve
- exception: Cricothyroid - superior laryngeal nerve
Where are the LMNs and UMNs located for the innervation of muscleso f the larynx
LMNs in nucleus ambiguus in rostral medulla
UMNs in corticobulbar tract in precentral gyrus
What is the sensory innervation of the laryngeal mucosa (hint- split into above vocal fold and below)
CNX
- above vocal fold: internal branch of laryngeal nerve
- below vocal fold: recurrent laryngeal nerve
Describe the cough reflex
Afferent CNX -> main and descending nucleus of t trigeminal nerve -> brainstem cough pattern generator-> controlling laryngeal muscles -> diaphragm and abdominal pain etc.
Efferent: CNX and various spinal nerves
Damage to the laryngeal nerves- what would you see?
Superior laryngeal nerve damage: Cricothyroid paralysed -> cant lengthen vocal cord, voice is hoarse and easily tires
Lung tumours can compress the recurrent laryngeal nerve
• Recurrent laryngeal nerve damage →
o All muscles on same side except cricothyroid are paralysed
o Ipsilateral vocal cord cant be abducted/adducted
o Initially vocal cord bowed laterally, later adducted (voice poor → okay)
o If recurrent laryngeal nerve is damaged bilaterally, later adduction may interfere with breathing
What is dysarthria
• Dysarthria → disturbance of articulation of speech
o Could be brainstem or cranial nerve problem, cerebellum, or other causes • Larynx – CN X • Tongue – CN XII • Palate – CN X • Facial muscles – CN VII
What is aphasia
• Aphasia → problems with production or comprehension of speech & writing
o higher cognitive dysfunction – cerebral cortex problem, usually left side
What is the lymphatic drainage of the larynx
to deep cervical nodes aloong internal jugular vein
What is the blood supply of the larynx?
ECA -> superior thyroid artery -> superior laryngeal artery
Subclavian artery -> thyrocervical trunk -> inferior thyroid artery -> inferior laryngeal artery
