The “Adam’s Apple” is a common term for the laryngeal prominence of the thyroid cartilage. Scientifically known as the prominentia laryngea, this feature is a notable part of neck anatomy. The term “Adam’s Apple” is thought to originate from folklore, possibly referencing the biblical story of the forbidden fruit getting lodged in Adam’s throat, or perhaps from a misinterpretation of the Hebrew phrase describing “a man’s swelling.” In some Southern American dialects, it’s playfully called a “goozle,” derived from the verb “to guzzle.”
The laryngeal prominence is a crucial external landmark in the neck, essential for anatomical orientation, particularly in medical procedures like a cricothyroidotomy. It is typically more pronounced in males than in females and becomes more prominent in males during puberty as a secondary sexual characteristic. Its primary function is to protect the vocal cords located behind it. The vocal folds attach to the thyroid cartilage internally, near the most prominent point of the Adam’s apple. During puberty, the larynx grows, especially in males, causing this anterior segment to enlarge further. This growth lengthens the vocal folds, resulting in the deepening of the male voice.
Structure and Function of the Adam’s Apple
The thyroid cartilage, the largest of the nine cartilages in the larynx, includes the Adam’s apple as its most visible part. This prominence is formed where the two cartilage halves meet in the neck’s midline during embryonic development. The Adam’s apple is significant not only anatomically but also culturally and historically.
As a secondary sexual characteristic, the Adam’s apple becomes more apparent around puberty, distinguishing between sexes, being notably larger in males. This has led to its cultural recognition as a “male” trait. The growth of the laryngeal prominence during puberty is believed to be linked to voice changes at this stage, though definitive research on this connection is limited to smaller cadaver studies.
Anatomical studies measure the interlaminar angle (ILA) at the vocal process level, showing an average of 90 degrees in males and 120 degrees in females. The wider angle in women results in less protrusion of the cartilage, making it less visible under the skin. Regardless of the angle, the fundamental role of the Adam’s apple—and the thyroid cartilage it is part of—is to shield the delicate vocal cords situated just behind and below it.
Embryological Development of the Thyroid Cartilage
The thyroid cartilage is derived from connective tissue, originating from the neural crest mesenchyme of the pharyngeal arch. Like other laryngeal structures, it develops embryologically from both the fourth and sixth pharyngeal arches.
Throughout fetal development, the thyroid cartilage increases in size, descends in the neck, and transforms from a funnel shape to a more cylindrical form. The two laminae of the cartilage fuse anteriorly, except at the very top, which forms the thyroid notch. In childhood, the laryngeal prominence is similar in both sexes. However, with the onset of puberty, the Adam’s apple becomes more pronounced in males due to a larger ILA and greater anterior angulation. This growth of the male larynx is primarily driven by hormonal changes, particularly increased testosterone levels. Calcification of the thyroid cartilage starts during puberty and continues into adulthood. By middle age, most adult males have heavily ossified thyroid cartilages.
Blood Supply and Lymphatic Drainage
The venous drainage around the thyroid cartilage is managed by the superior laryngeal vein, which is located superiorly. This vein emerges from the thyrohyoid membrane and joins the superior thyroid vein, which in turn flows into the internal jugular vein, moving upwards from the cricothyroid membrane level.
Arterial blood supply comes from branches of the external carotid artery. The superior laryngeal artery is positioned superiorly, while the superior thyroid artery is more inferior. The superior laryngeal artery branches off from the superior thyroid artery shortly after the latter originates from the external carotid artery, before the superior thyroid artery descends. The superior laryngeal artery travels alongside the internal branch of the superior laryngeal nerve and penetrates the thyrohyoid membrane.
Lymphatic drainage in this area is facilitated by the superior deep cervical nodes (level II) and the pretracheal nodes (level VI), which subsequently drain into the deep cervical lymphatic basins. The superior deep cervical chain is located beneath the sternocleidomastoid muscle, alongside the internal jugular vein and the accessory nerve. On the left side, this lymphatic drainage merges with the thoracic duct, and on the right, with the brachiocephalic vein (and sometimes an accessory thoracic duct).
Nerve Supply to the Laryngeal Area
The laryngeal prominence of the thyroid cartilage is a structural component providing support and protection, and it does not have its own specific nerve innervation. However, it is situated between the internal and external branches of the superior laryngeal nerve, which is a branch of the vagus nerve (CN X). The internal branch of the superior laryngeal nerve passes through the thyrohyoid membrane superiorly to provide sensory innervation to the laryngeal mucosa. Inferiorly, the external branch extends to innervate the cricothyroid muscle.
Other significant nerve structures in this region include the vagus nerve itself, located laterally in the carotid sheath, running downwards. The ansa cervicalis, another nerve structure, is situated deeper and more laterally, providing innervation to the strap muscles of the neck.
Muscles Associated with the Thyroid Cartilage
The thyrohyoid membrane connects the superior aspect of the thyroid cartilage to the hyoid bone located above it. The laryngeal prominence itself is directly linked to the hyoid bone by the median thyrohyoid ligament. The thyrohyoid muscle, innervated by CN XII and C1 spinal nerve, functions to depress the larynx.
The infrahyoid muscles, also known as “strap” muscles (including the sternohyoid and sternothyroid muscles), are positioned anterior to the thyroid cartilage and act to depress the hyoid bone. These muscles receive their nerve supply from the bilateral ansa cervicalis.
Surgical Considerations Involving the Adam’s Apple
Chondrolaryngoplasty, commonly referred to as a tracheal shave or laryngeal shave, is a cosmetic outpatient surgical procedure aimed at reducing the prominence of the Adam’s apple. It is considered a safe procedure with a high success rate and is often performed by surgeons specializing in gender affirmation for transgender individuals transitioning from male to female, or for anyone who desires a less prominent Adam’s apple for cosmetic reasons. In transgender patients undergoing gender affirmation surgeries, chondrolaryngoplasty might be combined with a crico-thyroidopexy to elevate the pitch of the voice.
The ala, or lamina, of the thyroid cartilage can also be harvested as donor tissue for cartilage grafts. It has been utilized in laryngotracheoplasty to repair tracheocutaneous fistulas in children and in laryngotracheal reconstruction to treat subglottic stenosis in pediatric patients.
Clinical Significance of the Adam’s Apple
The Adam’s apple is not only the most prominent but also one of the most clinically relevant laryngeal structures visible externally. Its location is vital in various surgical and emergency medical procedures, particularly for identifying the cricothyroid membrane when performing a cricothyroidotomy—an emergency airway procedure. Studies indicate that locating this anatomical landmark by palpation can be more challenging in females compared to males during emergencies, primarily due to the less pronounced angulation of the thyroid cartilage in females. Palpation can also be difficult in individuals with obesity.
Furthermore, as a secondary sex characteristic, the appearance of the Adam’s apple is a cosmetic consideration for some transgender individuals and those considering gender affirmation or reassignment surgery.
Review Questions
(Note: Review Questions and Figure are kept as in the original, as per instructions, focusing on content rewrite and SEO)
Figure: Surface Anatomy and Surface Markings, Front view of neck, Digastricus, Mylohyoideus, Hyoid bone, Thyroid cartilage, Cricoid cartilage, Sternal Head Henry Vandyke Carter, Public Domain, via Wikimedia Commons
References
1.Sturm A, Chaiet SR. Chondrolaryngoplasty-Thyroid Cartilage Reduction. Facial Plast Surg Clin North Am. 2019 May;27(2):267-272. [PubMed: 30940393]
2.Zamponi V, Mazzilli R, Mazzilli F, Fantini M. Effect of sex hormones on human voice physiology: from childhood to senescence. Hormones (Athens). 2021 Dec;20(4):691-696. [PMC free article: PMC8594207] [PubMed: 34046877]
3.Hsu CY. [Transgender and Gender Dysphoria: Viewpoints on Clinical Care and Psychological Stress]. Hu Li Za Zhi. 2023 Feb;70(1):17-22. [PubMed: 36647306]
4.Glikson E, Sagiv D, Eyal A, Wolf M, Primov-Fever A. The anatomical evolution of the thyroid cartilage from childhood to adulthood: A computed tomography evaluation. Laryngoscope. 2017 Oct;127(10):E354-E358. [PubMed: 28608401]
5.Lungova V, Thibeault SL. Mechanisms of larynx and vocal fold development and pathogenesis. Cell Mol Life Sci. 2020 Oct;77(19):3781-3795. [PMC free article: PMC7511430] [PubMed: 32253462]
6.Bunch PM, Hughes RT, White EP, Sachs JR, Frizzell BA, Lack CM. The Pharyngolaryngeal Venous Plexus: A Potential Pitfall in Surveillance Imaging of the Neck. AJNR Am J Neuroradiol. 2021 May;42(5):938-944. [PMC free article: PMC8115379] [PubMed: 33664114]
7.Shreevastava AK, Das RS, Maheshwari TP, Damodhar BK. Bilateral higher carotid termination with rare anomalous emergence of ventral branches of the external carotid arteries: A cadaver study. SAGE Open Med Case Rep. 2022;10:2050313X221138659. [PMC free article: PMC9747873] [PubMed: 36530368]
8.Kent DT, Schwartz AR, Zealear D. Ultrasound Localization and Percutaneous Electrical Stimulation of the Hypoglossal Nerve and Ansa Cervicalis. Otolaryngol Head Neck Surg. 2021 Jan;164(1):219-225. [PMC free article: PMC9508902] [PubMed: 33076752]
9.Kreukels BPC, Köhler B, Nordenström A, Roehle R, Thyen U, Bouvattier C, de Vries ALC, Cohen-Kettenis PT., dsd-LIFE group. Gender Dysphoria and Gender Change in Disorders of Sex Development/Intersex Conditions: Results From the dsd-LIFE Study. J Sex Med. 2018 May;15(5):777-785. [PubMed: 29606626]
10.Cheng J, Jacobs I. Thyroid ala cartilage graft laryngotracheoplasty for closure of large pediatric tracheocutaneous fistula. Int J Pediatr Otorhinolaryngol. 2013 Jan;77(1):147-9. [PubMed: 23073169]
11.Gaffey MM, Sun RW, Richter GT. A novel surgical treatment for posterior glottic stenosis using thyroid ala cartilage – A case report and literature review. Int J Pediatr Otorhinolaryngol. 2018 Nov;114:129-133. [PubMed: 30262350]
12.Schouela N, Woo MY, Pan A, Cheung WJ, Perry JJ. Perceived versus actual cricothyroid membrane landmarking accuracy by emergency medicine residents and staff physicians. CJEM. 2020 Jul;22(4):523-527. [PubMed: 32038001]
