Pharynx Larynx

• The quadrangular membrane is formed by the thyroid cartilage
• When you talk about larynx and pharynx, what comes to mind is voice production and swallowing
• Superior Parts and View of the Larynx

  Pre-epiglottic Space is behind the thyrohyoid ligament, Vallecula is the space between the base of tongue and epiglottis, Vestibular ligament and Vocal ligament are between the Arytenoids acting like gates, Ventricle is a space between the vestibular and vocal ligament
• The thyroid cartilage contains the adam's apple, which is prominent among men
• The thyroid cartilage is different from the thyroid gland, which is located below the neck along the trachea
• The hyoid bone is located at the angle formed by the neck and jaw
• The cricoid cartilage is connected to the thyroid cartilage by the cricothyroid membrane
• During phonation, vocal cords vibrate and hit each other
• Posterior Parts and View of the Larynx

  Epiglottis or epiglottic cartilage acts like a keel to divide the flow of food, Arytenoid cartilages move and rotate on top of cricoid cartilage, Corniculate cartilage is a green colored structure on top of Arytenoid cartilage, Cuneiform cartilage provides stability and rigidity to aryepiglottic fold
• Connus elasticus

  • A triangular ligament
  • Confluence of connective tissue
  • Edge is the vocal ligament creating the glottic fold/true vocal fold
  • Underlying this are the muscles
• Cartilage


  A ring-like structure
• The cricothyroid muscle is a superior laryngeal nerve exit branch and its action is to pull the thyroid cartilage downward and stiffen the vocal lig
• All the muscles of the larynx tend to close the airway, except the posterior cricoarytenoid
• Paraglottic space


  • Lateral to the glottic region
  • A potential space wherein cancer can spread
  • Partially inhibit mobility of the vocal cords when cancer is present
• Quadrangular Membrane

  • Formed by thyroid cartilage, epiglottis, arytenoid, vestibular ligament (false vocal cord/fold)
  • Acts like a funnel
  • Covered by connective tissue mucosa
  • Located between the epiglottis and false vocal fold
• Cricothyroid membrane

  • Can be palpated externally at the Adam’s apple
  • The airway can be accessed by puncturing this
• Posterior cricoarytenoid muscle

  1. Abductor

  2. Opens the arytenoid to open the airway

  3. When contracts, it pulls muscular process then the arytenoid rotates outward, the vocal process of the arytenoid moves laterally, and the airway is opened
• The interarytenoid muscle, lateral cricoarytenoid muscle, and the buccalis(?) will tend to close the larynx
• Uccalis will tend to close the larynx


  Posterior cricoarytenoid will open it
• All intrinsic muscles of the larynx are innervated by the recurrent laryngeal nerve or the inferior laryngeal nerve
• Thyroarytenoid muscle
• Superior laryngeal nerve
• Internal branch of superior laryngeal nerve
• Vocalis muscle
• Inferior laryngeal nerve
• Exception to the rule: Cricothyroid muscle is supplied by the superior laryngeal nerve
• Cricothyroid muscle action
• Recurrent laryngeal nerve
• External branch of superior laryngeal nerve
• Lateral crico-arytenoid muscle action
• Bernoulli effect created within the true vocal folds due to the air coming from the lungs
• All intrinsic muscles to the larynx are innervated by the Recurrent Laryngeal Nerve
• Anatomy of the larynx

  • Hyoid bone
  • Thyroid cartilage
  • Cricoid cartilage
  • Membranes
  • Arytenoid cartilage
• Vocal cord abduction and adduction

  1. Abductor: Posterior Cryco-Arytenoid muscle and Recurrent Laryngeal Nerve

  2. Adductor: Lateral Cryco-Arytenoid muscle and Recurrent Laryngeal Nerve, Inter-Arytenoids muscle and Recurrent Laryngeal Nerve

  3. Shortens and Adducts (pitch): Thyro-Arytenoid muscle and Recurrent Laryngeal Nerve

  4. Tenses and lengthens (pitch): Cryco-Thyroid muscle and Extrinsic branch of Superior Laryngeal Nerve
• In theory, a voice can be produced even if one is already dead by blowing air in a dead larynx or cadaveric larynx
• When a person articulates, it involves the tongue, oral cavity, teeth, soft palate, and lips
• When a person produces consonants, several components of the oral cavity and the oropharynx are involved
• Action of the cryco-thyroid muscle

  Swivels the thyroid cartilage anteriorly with the cryco-thyroid joint, which consequently tenses the vocal ligament with increased pitch
• Producing voice and sound involves Power (Lungs), Vibrator (Larynx), Resonator (Supraglottic, nasal cavity, and oropharynx)
• When a person produces vowels, usually the larynx is the only one being used with some manipulation of the oral cavity and the oropharynx