The thyroid cartilage is a prominent and significant structure located in the human neck. This specialized piece of cartilage forms an integral part of the larynx, commonly known as the voice box.
Anatomical Placement
The thyroid cartilage is situated in the anterior part of the neck, positioned superior to the trachea, or windpipe. It lies inferior to the hyoid bone, to which it is connected by the thyrohyoid membrane. This cartilage serves as the largest of the nine laryngeal cartilages, forming the anterior and lateral walls of the larynx, which encases the vocal cords. It is composed of two broad, flat plates, known as laminae, that fuse anteriorly in the midline, creating an angle that is often externally visible as the laryngeal prominence. The superior border of the thyroid cartilage is typically found at the level of the C4 vertebra.
How to Identify It
Locating the thyroid cartilage on oneself is relatively straightforward due to its distinctive shape and position, and it is widely recognized as the “Adam’s apple,” the visible protrusion in the neck. This prominence is generally more noticeable in adult males because hormonal influences during puberty cause a sharper angle of fusion between the two laminae, approximately 90 degrees, compared to about 120 degrees in females. To palpate it, one can start by placing a finger under the chin and slowly moving it downwards along the midline of the neck. The first hard, angular structure encountered, which moves noticeably when swallowing, is the thyroid cartilage. This differentiates it from softer tissues above and the ring-shaped cricoid cartilage located just below it.
Function in the Body
Its rigid structure provides a protective shield for the delicate internal components of the larynx, especially the vocal cords, safeguarding them from external trauma. This protective function helps maintain the integrity of the airway. Beyond protection, the thyroid cartilage plays a significant role in voice production. It serves as an attachment point for the vocal cords, and its movements, facilitated by muscles, allow for adjustments in vocal cord tension. This enables the modulation of voice pitch and volume as air passes through, causing the vocal cords to vibrate and produce sound.