Which vertebral levels correspond to the position of the larynx?
"The larynx lies at the level of C3 to C6 vertebrae.
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What are the cartilages of the larynx?
The larynx consists of nine cartilages joined by a number of membranes and ligaments. The nine cartilages can be divided into:
3 unpaired (in the midline)
Thyroid
Cricoid
Epiglottic
3 paired (bilateral)
Arytenoid (x2)
Corniculate (x2)
Cuneiform (x2)
What is the blood supply to the larynx?
"The larynx is supplied by laryngeal branches of the superior and inferior thyroid arteries.
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Name the extrinsic and intrinsic membranes of the larynx.
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The extrinsic membranes connect the laryngeal cartilage to the surrounding structures for support. They include the:
- Thyrohyoid
- Hyoepiglottic ligament
- Thyroepiglottic ligament
- Cricotracheal
The intrinsic membranes include the:
- Quadrangular
- Cricothyroid
Name the extrinsic muscles of the larynx and their function.
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Extrinsic muscles move the larynx as a whole.
- Suprahyoid (elevates the larynx)
- Stylohyoid
- Mylohyoid
- Geniohyoid
- Digastric muscle
- Infrahyoid (depresses the larynx)
- Sternothyroid
- Sternohyoid
- Thyrohyoid
- Omohyoid
Name the intrinsic muscles of the larynx.
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- Abductors/adductors (muscles to open and close the vocal cords)
- Adductor: Lateral cricoarytenoid muscle (main), transverse arytenoids muscles
- Abductor: Posterior cricoarytenoid muscles
- Sphincters (muscles to close the laryngeal inlet during swallowing)
- Lateral cricoarytenoid
- Transverse arytenoids
- Oblique arytenoids
- Tensors (muscles to raise pitch of voice)
- Cricothyroid muscle
- Relaxers (muscles altering pitch of voice)
- Thyroarytenoid
- Vocalis
What is the function of the intrinsic muscles of the larynx?
"The intrinsic muscles move and alter the length and tension of the vocal cords and the size and shape of the rima glottidis.
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Name the subdivisions of the laryngeal cavity.
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The laryngeal cavity may be divided into three major regions:
- Vestibule
- Middle (ventricle/laryngeal sinus)
- Infraglottic space
Name some causes of a vocal cord palsy.
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- Malignancy (30%) especially of the bronchus, oesophagus, thyroid gland, nasopharynx.
- Iatrogenic (25%) in thyroid, parathyroid, oesophageal, pharyngeal pouch and left lung surgery.
- External trauma (15%).
- Idiopathic (15%).
- Others (15%) in neurological disorders, myopathies.
What are the different types of vocal cord palsies?
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The different types of vocal cord palsy include:
- Unilateral or bilateral
- Temporary or permanent
What is the clinical significance of a bilateral recurrent laryngeal nerve palsy?
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- Bilateral recurrent laryngeal nerve palsy presents with stridor.
Note: Unilateral recurrent laryngeal nerve palsy presents with hoarseness
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