The structure commonly called the “Adam’s Apple” is a noticeable feature in many people, yet its presence often raises questions about biological sex. While typically associated with males, the structure itself is not exclusive to one sex. All humans possess the underlying anatomical components, but the degree of its visibility varies significantly. This difference is rooted in hormonal changes during puberty, which dictate the growth and shape of the voice box.
Defining the Laryngeal Prominence
The visible bulge in the front of the neck is anatomically known as the laryngeal prominence. This structure is formed by the thyroid cartilage, the largest piece of cartilage in the larynx, or voice box. The thyroid cartilage is a shield-shaped structure composed of two plates, called laminae, that join together at the front of the throat.
The primary function of this cartilage is to protect the delicate vocal cords and the airway housed within the larynx. Because this cartilage is essential for speech and breathing, it is present in every person. The informal term “Adam’s Apple” arose because the structure’s protrusion becomes much more pronounced and visible in males after adolescence.
Structural Differences in Male and Female Larynges
Before puberty, the laryngeal anatomy is similar in size and structure for both sexes. The onset of adolescence initiates growth and change in the larynx, driven primarily by sex hormones. In males, the surge of testosterone triggers a rapid and significant growth spurt in the thyroid cartilage.
This hormonal influence causes the cartilage to grow larger and elongate, pushing it forward to create the distinct prominence. The angle where the two cartilage laminae meet narrows considerably, shifting from a wider pre-pubescent angle (around 120 degrees) to a sharper angle (closer to 90 degrees) in adult males. This sharpening of the angle makes the protrusion prominent.
The growth also extends the vocal cords from about 1.0 centimeter to approximately 1.6 centimeters. This lengthening and thickening of the vocal cords lowers the fundamental frequency, causing the male voice to deepen by about an octave.
The female larynx also experiences growth during puberty, but the change is less dramatic. Estrogen causes the female larynx to grow only slightly, and the angle of the thyroid cartilage laminae remains wider, preventing a noticeable external protrusion. The female vocal cords lengthen modestly, resulting in a voice pitch drop of only about one-third of an octave. The adult female thyroid cartilage is roughly 20% smaller compared to the male structure.
Causes of Prominence in Females
Even though the laryngeal prominence is typically not visible in females, some women or girls may have a noticeable protrusion. One reason is natural anatomical variation, as some females naturally have a slightly larger or more acutely angled thyroid cartilage. This anatomical difference alone can lead to greater visibility.
More pronounced cases are often linked to endocrine factors, specifically conditions that result in higher levels of circulating androgens. Androgens, like testosterone, stimulate the growth of laryngeal structures, mimicking male pubertal development. The increased presence of these hormones leads to an enlarged thyroid cartilage.
Conditions such as Polycystic Ovary Syndrome (PCOS) or Congenital Adrenal Hyperplasia (CAH) can cause hyperandrogenism, which may lead to laryngeal virilization. This hormonal influence can cause the voice to significantly deepen by lowering the fundamental frequency. If the exposure to androgens is long-standing, the resulting changes, including the enlargement of the thyroid cartilage and deepening of the voice, can become permanent.