What are the superior and inferior boundaries of the larynx?
Sup: Hyoid bone (C4)
Inf: Trachea (C6)
What are the functions of the larynx?
- Protection of airways
- Cough reflex
What are the zones of the larynx, and their corresponding sensory innervation:
Supraglottis = Internal laryngeal nerve
Subglottis = Recurrent laryngeal nerve
What are the cartilages of the larynx?
Which membrane of the larynx is can be punctured to establish an emergency airway?
What is the name of the point where the 2 lateral plates of the thyroid cartilage meet?
Laryngeal prominence ‘adam’s apple’
Name the only complete ring of cartilage in the respiratory tract:
Broadly, how do the intrinsic laryngeal muscles affect the arytenoids?
The muscles cause the arytenoids to pivot on the cricoid cartilage, causing the vocal cords to abduct/adduct/tense
Name the 2 mucosal folds lining the interior of the larynx:
Most superior = vestibular fold (false vocal cord)
Inferior = true vocal cord (contains vocal ligament)
Name the 5 intrinsic muscles of the larynx:
2) Post. cricoarytenoid
3) Lat. cricoarytenoid
5) Transverse + Oblique arytenoids
Which muscle is responsible for changing pitch during phonation (particularly high pitch sounds)? What is its nerve supply?
Ext. superior laryngeal (CN X)
Which muscle can abduct the vocal cords, therefore required for respiration? What is its nerve supply?
Recurrent laryngeal (CN X)
Which nerve innervates all (except one) of the intrinsic muscles of the larynx? What is the exception?
Recurrent laryngeal nerve
Exception = Cricothyroid = Ext. superior laryngeal
Describe the position of the vocal cords during:
ADDUCTED = phonation, coughing, swallowing
ABDUCTED = respiration
What happens to the corresponding vocal cord if the left recurrent laryngeal nerve is cut? How will this present?
- Immobilise in neutral position between abduction and adduction
- Hoarse voice, weaker cough
What happens to the vocal cords if both the recurrent laryngeal nerves are cut? How will this present?
- Both vocal cords immobilise in neutral position
= Rima glottis becomes extremely narrow
- Aphonia, obstructed breathing, unable to protect airway during swallowing
Name some concerning causes of a hoarse voice:
- Left apical lung tumour (pancoast)
- Aortic aneurysm
- Enlarged lymph nodes in trachea-oesophageal groove
- Carcinoma of larynx
Which nerves make up the cervical plexus, and in which triangle of the neck is it located?
Name the main 2 motor branches of the cervical plexus, their roots and target:
Phrenic = C3, 4, 5 –> Diaphragm
Ansa cervicalis = C1, 2, 3 –> Infrahyoids
Name the main 4 sensory branches of the cervical plexus, and their targets:
- Greater auricular –> Ear
- Transverse cervical –> Anterior neck
- Lesser occipital –> Post-Sup scalp
- Supraclavicular –> Upper thoracic region