Larynx Flashcards
How can the larynx be subdivided?
SUPRAGLOTTIS = inferior surface of epiglottis, vestibular folds (false cords - pink outpouchings of tissue)
GLOTTIS = vocal cords (1cm inferior, white and pristine)
SUBGLOTTIS = down to lower border of cricoid cartilage
What are the piriform fossae?
Pair of mucosal recesses between the central part of the larynx and the lateral lamina of the thyroid cartilage
Form channels which direct solids and liquids from the oral cavity, around the raised laryngeal inlet, and into the oesophagues
What is the structure of the epiglottis?
Leaf-shaped plate of elastic fibrocartilage, attached posteriorly to thyroid cartilage by thyroepiglottic ligament
What is the vallecula?
Depression between tongue base and epiglottis
Describe the features of the thyroid cartilage.
Adam’s apple = laryngeal prominence
Largest cartilage comprised of two lamina
Superior thyroid horns (hyoid horns) and inferior thyroid horns (cricoid horns)
Lateral thyroid ligaments attach superior horns to hyoid bone
Describe the features of the cricoid cartilage.
Most inferior cartilage
Completely encircles the airway (only complete circle of cartilage in the body)
2 articular facets on each side (superolateral —> arytenoid cartilage, lateral —> medial surface of inferior horn of thyroid cartilage)
Describe the features of the arytenoid cartilage.
Pyramid-shaped
Concave base articulates with cricoid
Attached to vocal cords posteriorly (involved in vocal cord movement)
What are the layers and muscles of the vocal cords?
Layers:
Stratified squamous epithelium —> Reinke’s space (oedematous layer) —> vocal ligament —> vocalis muscle
Muscles:
ABduction = posterior cricoarytenoid
ADduction = lateral cricoarytenoid
note: all vocal cord associated muscles are supplied by the recurrent laryngeal nerve, except for the cricothyroid muscle (external laryngeal nerve)
How can you assess the vocal cords?
Stroboscopy
Instrument used to make cyclically moving objects appear to be slow moving or stationary. When the vibrating object is observed through a stroboscope at its vibration frequency, it appears stationary
Ask patient to hum whilst looking through the stroboscope
What is the blood supply of the larynx?
ARTERIES = superior & inferior laryngeal arteries (branches of superior & inferior thyroid arteries, themselves branches of the external carotid artery)
VEINS = superior & inferior laryngeal veins
What is the nervous supply to the larynx?
Superior & recurrent laryngeal nerves
Superior laryngeal nerve (deep to carotid arteries) branches:
- internal laryngeal nerve = sensory (pierces thyrohyoid membrane)
- external laryngeal nerve = motor (cricothyroid muscle) - deep to superior thyroid artery
Recurrent laryngeal nerves (in tracheo-oesophageal groove):
- right = under right subclavian artery
- left = under aortic arch
What are some causes of recurrent laryngeal nerve palsy?
- idiopathic
- laryngeal cancer
- thyroid disease (benign or malignant)
- trauma (inc. iatrogenic - surgery)
- aortic aneurysm/subclavian aneurysm
- cervical lymphadenopathy
- oesophageal cancer
- apical lung cancer (Pancoast’s tumour)
- neuropathies (diabetes —> nerve lesions)
Contrast hypopharyngeal and laryngeal carcinomas.
Hypopharyngeal = post-cricoid, piriform fossa, posterior pharyngeal wall
Laryngeal (smoking & alcohol) = supraglottis, glottis, subglottis (more superior - better prognosis)
90%+ squamous cell carcinoma
note: not associated with HPV (oropharyngeal cancer)
What are the signs and symptoms of hypopharyngeal and laryngeal carcinomas?
- foreign body sensation in throat
- dysphagia
- odynophagia
- otalgia (referred pain along vagus nerve)
- hoarseness
- coughing (aspiration, haemoptysis)
- weight loss
- smoking history
What is the examination, investigations, and management for hypopharyngeal and laryngeal carcinomas?
Examination:
- loss of laryngeal crepitus (unable to move laryngeal prominence)
- cervical lymph nodes metastases
Investigations:
- barium swallow
- CT/MRI head, neck, & chest
- pharyngo-laryngo-oesophagoscopy + biopsy
Management: radiotherapy +/- chemotherapy, surgery
