Pharynx + Larynx Flashcards
What are the 3 divisions of the pharynx?
Nasopharynx
Oropharynx
Laryngopharynx
Where is the nasopharynx located?
Anterior border = Continuous with the nasal cavity
Posterior border = C1 vertebral body
Inferior border = Lower body of soft palate
What are the functions of the larynx?
Primary: protect the tracheobronchial tree
Prevents inhalation of food/liquids (aspiration)
Enables phonation
What nerve supplies motor innervation to the larynx?
Recurrent laryngeal branch (of CNX) - all laryngeal muscles except the cricothyroid which is innervated by the superior laryngeal nerve (branch of CN X)
What is the function of the lateral cricoarytenoid muscles?
Internal rotation of the arytenoid cartilage and adduction of the vocal cords to protect airways by preventing aspiration
What is the function of the posterior cricoarytenoid muscles?
Abduction and external rotation of the arytenoid cartilage to open vocal cords for breathing
What nerve supplies sensory innervation to the larynx?
Above vocal folds = superior laryngeal (CN X)
Below vocal folds = recurrent laryngeal (CN X)
What might be the consequence of unilateral or bilateral damage to the superior laryngeal nerve supply?
Loss of sensation above vocal folds
Inability to depress thyroid cartilage - low pitch voice
What might be the consequence of a unilateral loss of recurrent laryngeal nerve supply?
Flaccidity to ipsilateral vocal fold - can be asymptomatic or have some voice disturbance (hoarseness) but little effect on respiratory system
What might be the consequence of a bilateral loss of recurrent laryngeal nerve supply?
Severe stridor/ impaired breathing
Hoarse voice
What is the arterial supply to the larynx?
Superior laryngeal (branch of superior thyroid) Inferior laryngeal (branch of inferior thyroid)
Why is the cricothyroid ligament clinically relevant?
Can be incised in emergency situations to insert tracheostomy tube when there is an obstruction in the larynx (or above) and intubation has been unsuccessful
What anatomical feature prevents food from entering our nasal cavity?
Soft palate muscles close communication between the nasopharynx and oropharynx when eating:
Tensor Veli Palatini (stretches palate)
Levator Veli Palatini (lifts palate)
How does epithelium change as you move down the pharynx?
Transitions from pseudostratified ciliated columnar epithelium to stratified squamous epithelium
What are the borders of the oropharynx?
From the upper border of the soft palate to the lower border of the epiglottis
What are the borders of the laryngopharynx?
Base of tongue/upper epiglottis to the cricopharyngeus muscle
What is the sensory nerve innervation to the pharynx?
Nasopharynx = CN Vb + CN IX Oropharynx = CN IX Laryngopharynx = CN IX + CN X
What 3 muscles make up the pharynx?
Superior, middle and inferior constrictors (lined by continuous internal fascia and mucosa)
What does contraction of the pharynx muscles result in?
Reduce diameter of pharynx tube to squeeze food down (by peristalsis)
What might damage to the vagus nerve result in?
Dysphagia
Risk of aspiration (which can lead to pneumonia)
Compromised gag reflex
What is Eagle syndrome?
Unusually long styloid processes causing difficulty swallowing and the feeling of something in throat (caused by bone sticking into soft muscle)
Where is the ‘weak spot’ in the pharynx and what may be the clinical consequence of this?
Gap between muscle fibres of the inferior constrictor muscle and the cricopharyngeus
Potential point of herniation of pharyngeal tissue
What is the midline Raphe?
Posterior attachment point for constrictor muscles - extends from the base of the skull to the ‘weak spot’
What is a normal swallowing process?
- Coordinated peristalsis of constrictors
- Relaxation of cricopharyngeus muscle
- Drop in intrapharyngeal pressure to allow food to progress downwards
What is a Zenker diverticulum?
Posteriorly herniated pharyngeal lining at ‘weak spot’ forming pouch where food can get stuck
Can result in halitosis and coughing up of old food
What is the function of the thyroarytenoid muscle?
Relaxes the vocal cords during speech to lower pitch
What is the motor innervation to the muscles of the pharynx?
All CN X innervated except:
Tensor Veli Palatini - CN Vc
Stylopharyngeus - CN IX
