An old man presented with hoarseness, cough, dysphagia, and foreign body sensation in the throat. Laryngocele was suspected. Laryngocele arises from herniation through:

A laryngocele is defined as an abnormal dilation or herniation of the saccule of the larynx. Laryngoceles can be classified into three types: internal, external, and combined. A laryngocele is defined as internal if the dilation lies within the limits of the thyroid cailage. If the laryngocele extends beyond the thyroid cailage and protrudes through the thyrohyoid membrane producing a lateral neck mass, it is considered external.