Laryngeal Cancer

Question 1

What are the common risk factors?

Answer 1

Radiation to the area, smoking, alcohol, family history, immunosuppression, certain infections (HPV, HIV), GORD, age, gender (male)

Question 2

Investigations (excluding ancillary tests)

Answer 2

CT neck with contrast, laryngoscopy, FNA of any neck masses, CT chest/abdo/pelvis or PET to stage the disease, laryngeal biopsy

Question 3

What are the cartilages of the larynx?

Answer 3

There are 3 unpaired - the epiglottis, the thyroid cartilage, and the cricoid cartilage.
There are 3 paired cartilages - the arytenoid cartilages, the cuneiform cartilages, and the corniculate cartilages

Question 4

Blood supply and drainage of the larynx

Answer 4

Arterial supply - superior laryngeal artery from the superior thyroid artery from the external carotid artery, a branch of the common carotid. Also, the inferior laryngeal artery, a branch of the inferior thyroid artery which is a branch from the subclavian artery.

Drainage - inferior laryngeal veins which drain into inferior thyroid which then drain into the brachiocephalic veins (mostly the left).

Question 5

Epithelium of the larynx?

Answer 5

Most are the same as the respiratory tract - pseudostratified columnar ciliated epithelium. The vocal folds are lined by stratified squamous epithelium to cope with abrasion from talking.

Question 6

Describe the nerve supply of the muscles of the larynx.

Answer 6

Recurrent laryngeal nerves (from vagus) supply most of the muscles of the inferior neck except for cricothyroid muscle, which is supplied by the external laryngeal nerve.

Supraglottic is supplied by superior laryngeal nerve. Vocal folds receive proprioception and touch by superior laryngeal nerve.

Question 7

What are the muscles involved in phonation?

Answer 7

• Opening/abduction: posterior cricoarytenoid.
• Adduction/closing (3): lateral cricoarytenoid, transverse arytenoid, and oblique arytenoid.

Lengthening of vocal cord is done by cricothyroid muscle, and shortening is by thyroarytenoid muscle. Thyroarytenoid muscle opposes cricothyroid muscle.

Question 8

What is the innervation for recurrent laryngeal nerve?

Answer 8

It provides all motor supply for larynx except cricothyroid muscle.

Right recurrent laryngeal nerve loops below right subclavian, and left recurrent laryngeal nerve loops under aortic arch.

External laryngeal nerve supplies cricothyroid muscle.

They derive motor fibres from cranial part of the accessory nerve from cell bodies in nucleus ambiguus.

Question 9

Where does laryngeal cancer spread to?

Answer 9

• Locally to the cartilages
• Cervical chain lymph nodes
• Lung, liver, bone