The laryngeal prominence, commonly known as the Adam’s apple, is the visible protrusion located at the front of the neck. This structure is a distinct, external feature of the larynx, or voice box, situated just above the trachea. It acts as an important superficial landmark for the underlying airway and vocal apparatus.
Anatomy and Composition
The laryngeal prominence is formed by the thyroid cartilage, the largest of the nine cartilages that make up the larynx. This shield-shaped structure consists of two broad, flat plates called laminae, which join together at the front of the throat, meeting at an angle in the midline.
The point where the two laminae fuse anteriorly forms the apex of the structure, which projects outward and is externally visible. The hyaline cartilage provides structural support for the entire larynx. Located directly behind this protrusion, on the inner surface of the cartilage, are the delicate vocal folds.
The thyroid cartilage is situated superior to the cricoid cartilage, a complete ring that marks the inferior border of the larynx. The entire laryngeal framework sits in the anterior neck, positioned in front of the pharynx and at the top of the trachea. This location allows the thyroid cartilage to completely encase and protect the internal components of the voice-producing organ.
Function in Vocalization
The primary biological role of the thyroid cartilage is to act as a protective shield for the airway. It forms a robust anterior barrier that encases the larynx, safeguarding the delicate vocal folds from physical trauma.
The thyroid cartilage also plays a direct mechanical part in manipulating the voice. The vocal folds are attached to the inner surface of the cartilage at the front and to smaller, movable arytenoid cartilages at the back. Muscles connect the thyroid cartilage to other laryngeal components, allowing for controlled movement.
For instance, the cricothyroid muscle links the thyroid cartilage to the cricoid cartilage below it. When this muscle contracts, it tilts the thyroid cartilage forward, which stretches and tenses the vocal folds. This adjustment in tension and length raises the pitch of the voice.
The size and shape of the thyroid cartilage influence the overall resonance of the voice. A larger laryngeal framework correlates with longer vocal folds and a larger resonating chamber. This physical structure helps determine the unique acoustic qualities and depth of an individual’s vocal sound.
Developmental Changes and Prominence
The visibility of the laryngeal prominence varies significantly among individuals, developing as a secondary sex characteristic during puberty. The enlargement and change in shape of the thyroid cartilage are driven by increased testosterone levels during adolescence, which stimulates a growth spurt in the laryngeal tissues.
In individuals assigned male at birth, the thyroid cartilage grows substantially larger, and the angle where the laminae meet becomes more acute. This sharper angle, averaging around 76 degrees post-puberty, causes the cartilage to protrude outward significantly, resulting in a distinct, visible prominence. This rapid growth also causes the vocal folds to lengthen and thicken.
In contrast, in individuals assigned female at birth, laryngeal growth is less dramatic, and the angle of the thyroid cartilage remains wider. This wider angle, averaging around 94 degrees, prevents the same degree of anterior projection. Consequently, the prominence is smaller and less noticeable beneath the skin.
The difference in laryngeal size and vocal fold length between the sexes results in a lower-pitched voice in males following puberty. The pronounced external appearance of the laryngeal prominence is the most visible marker of this internal anatomical transformation occurring under the influence of sex hormones.