This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
External laryngocele is a herniation that arises from which of the following membrane? 
Select and explain. 
A. Thyrohyoid membrane, B. Cricoepiglottic membrane, C. Thyroid membrane, D. Cricovocal membrane
A: Thyrohyoid membrane
Answer: A: Thyrohyoid membrane 
Explanation: A laryngocele is an air filled herniation of the saccule of the laryngeal ventricle. It is caused by a prolonged increase in intraglottic pressure in patients with a predisposing long sacculus. Laryngoceles are of two types internal and external. Internal laryngocele: are confined within the larynx and appear as cystic swellings of the aryepiglottic fold. External laryngocele: extend through the thyrohyoid membrane and lie lateral to the thyroid cailage.