Anatomy of Upper Respiratory System Quiz

Palatine Tonsils and Laryngopharynx

• The palatine tonsils are located in the laryngopharynx, which lies behind the larynx.
• The laryngopharynx extends from the upper border of the epiglottis to the level of the cricoid cartilage.
• It also contains pyriform fossa, one on each side of the inlet of the larynx.

Larynx

• The larynx is a specialized organ that has three functions: airway passage (respiration), phonation, and protective sphincter at the inlet of air passages (cough).
• It is located in front of the laryngopharynx, opposite the 3rd, 4th, 5th, and 6th cervical vertebrae.
• The larynx begins at the 3rd cervical vertebra and ends at the 6th cervical vertebra, continued by the trachea.

Cartilages of the Larynx

• The larynx has three single cartilages: epiglottis, thyroid, and cricoid.
• It also has three paired cartilages: arytenoid, corniculate, and cuneiform.
• The epiglottis is a leaf-shaped elastic cartilage that lies behind the root of the tongue.
• The thyroid cartilage is the largest cartilage of the larynx, consisting of two laminae of hyaline cartilage that meet in the midline.
• The cricoid cartilage is a signet-shaped ring of hyaline cartilage that lies between the thyroid cartilage and trachea.
• The arytenoid cartilages are two small pyramidal-shaped cartilages situated above the lamina of the cricoid cartilage.

Membranes and Ligaments of the Larynx

• The extrinsic membranes of the larynx include the thyrohyoid membrane and the cricotracheal ligament.
• The intrinsic membranes of the larynx include the quadrangular membranes and the cricothyroid ligament.
• The quadrangular membranes extend between the epiglottis and arytenoid cartilages, forming the aryepiglottic fold and the vestibular ligaments.
• The cricothyroid ligament extends between the cricoid and thyroid cartilages, forming the vocal ligament (vocal cords).

Inlet of the Larynx

• The inlet of the larynx looks backward and upward into the laryngopharynx and is bounded by the epiglottis, aryepiglottic fold, and mucous membrane.

Cavity of the Larynx

• The cavity of the larynx has two pairs of folds and two spaces between them: the vestibular folds and the rima vestibuli, and the vocal folds and the rima glottis.
• The cavity is divided into three regions: the vestibule (supraglottic), the sinus of the larynx (ventricle), and the lower laryngeal region (infraglottic).

Muscles of the Larynx

• The extrinsic muscles of the larynx include the elevators (suprahyoid muscles) and the depressors (infrahyoid muscles).
• The intrinsic muscles of the larynx include the muscles controlling the inlet of the larynx and the muscles controlling the vocal cord movements.
• The muscles controlling the inlet of the larynx include the aryepiglottic muscle and the thyroepiglottic muscle.
• The muscles controlling the vocal cord movements include the posterior cricoarytenoid muscle, the lateral cricoarytenoid muscle, the transverse arytenoid muscle, the cricothyroid muscle, the thyroarytenoid muscle, and the vocalis muscle.

Nerve Supply of the Larynx

• The motor nerve supply of the larynx is provided by the recurrent laryngeal nerve, except for the cricothyroid muscle, which is supplied by the external laryngeal nerve.
• The sensory nerve supply of the larynx is provided by the internal laryngeal nerve above the level of the vocal cords and the recurrent laryngeal nerve below the level of the vocal cords.

Blood Supply of the Larynx

• The blood supply of the larynx is provided by the superior thyroid artery and its superior laryngeal branch, and the inferior thyroid artery and its inferior laryngeal branch.

Lymphatic Drainage of the Larynx

• The lymphatic drainage of the larynx is divided into two regions: above the level of the vocal cords, which drains to the upper deep cervical lymph nodes, and below the level of the vocal cords, which drains to the prelaryngeal, pretracheal, and lower deep cervical lymph nodes.

Applied Anatomy

• Injury to the external laryngeal nerve can lead to paralysis of the cricothyroid muscle, resulting in a low-pitched voice and loss of sensation above the vocal cords.
• Injury to the recurrent laryngeal nerve can lead to paralysis of the vocal cords, affecting speech and breathing.