Cartilage Of Larynx

LARYNGEAL FRAMEWORK:
  1. Cartilages
  2. Joints
  3. Ligaments Membranes
  4. Muscles
  5. Mucous membrane
  6. Hyoid Bone
CARTILAGES OF LARYNX :
  • Elastic cartilage are Found in inlet of larynx
  1. Paired
  2. Unpaired
Paired :
  1. Arytenoid
  2. Corniculate
  3. cunieform
2. Unpaired:
  1. Thyroid
  2. Cricoid
  3. Epiglottic
Thyroid Cartilage:
  • Located anterior to the 4th and 5th cervical vertebrae.
  • It is a hyaline cartilage
  • Formed by 2 laminae which fuse ventrally in the midline of the neck, forming a protuberance, the laryngeal prominence or "Adam's apple,“
  • The 2 laminae meet at an angle of 90° in the male and 120° in the female.
  • The upper limit of fusion of the two laminae forms the superior thyroid notch
  • Posterior border of each lamina extends upward and downward as hornlike projections,the superior and inferior cornua
  • The cornua are characterized further at their origins from the thyroid laminae by superior and inferior tubercles.
  • Both of the superior horns are anchored to the tips of the greater horns of the hyoid bone;
  • Both inferior horns articulate with the cricoid cartilage.
  • On the lateral, external surface of each thyroid lamina is—ridge ,called the oblique line,
  1. Attaches to 3 muscle
  2. Sternothyroid,
  3. Thyrohyoid,and
  • Thyropharyngeus (a portion of the inferior pharyngeal constrictor).
  • The thyrohyoid membrane and median thyrohyoid ligament are attached to the upper border of the thyroid cartilage.
  • The lateral thyrohyoid ligaments attach to the greater cornua of the thyroid cartilage.
  • The cricothyroid ligaments (cricothyroid membrane) attach to the inferior border of the thyroid cartilage
  • 5 ligaments attach as one to the posterior surfaces of the thyroid laminae near the union of the laminae (angle):
  • The median thyroepiglottic ligament,
  • The 2 vestibular ligaments,And
  • The 2 vocal ligaments.
Cricoid Cartilage:
  • Shaped like a signet ring.
  • Cricoid is the narrowest part of infantile larynx
  • The narrowest part of trachea in a newborn is at the level of cricoid
  • Signet-shaped portion of the cricoid faces posteriorly
  • The arch is located anteriorly,
  • The cricoid cartilage is situated at vertebral level C6 (occasionally reaching the middle of C6), just below the thyroid cartilage
  • The cricoid lamina has 2 superior facets– articulate with the arytenoid cartilages and attach to them by the posterior cricoarytenoid ligaments
  • Lower lateral facets of the lamina articulate with the inferior horns of the thyroid cartilage.
  • The lower border of the cricoid cartilage is joined to the first tracheal ring by means of the thick cricotracheal ligament.
  • Arising from the arch of the cricoid cartilage anteriorly and externally are the cricothyroid muscles.
  • The lamina has a midline ridge for the tendinous attachment of longitudinal fibers of the esophagus.
  • The oesophgus commences at lower end of cricoid
  • Lateral to this ridge are the sites of origin for the bilateral posterior cricoarytenoid muscles
  • Almost pyramidal in shape, with 3 surfaces,a base, and an apex.
  • Each triangle-shaped base articulates with the cricoid cartilage by way of a diarthrodial joint.
  • Base has 2 processes:
  • Anteromedially directed vocal process – vocal ligament is attached
  • Short, broad, laterally projecting Muscular process – lateral and posterior cricoarytenoid muscles are attached
Arytenoid
  • It has 3 surfaces
  1. Posterior surface —Transverse and oblique arytenoid muscles attach
  2. Medial surface – covered with mucous-secreting laryngeal mucosa.
  3. Anterolateral surface –insertion of thyroarytenoid muscle,Part of the vocalis muscle,and the vestibular ligament.
  • The apex of the arytenoid cartilage supports the corniculate cartilage
Corniculate Cartilages ( of Santorini ):
  • Small fibroelastic nodules that sit on the apices of the arytenoid cartilages.
  • It has little functional importance in humans
CUNEIFORM CARTILAGES (OF WRISBERG)
  • Rod-shaped (like ancient cuneiform script).
  • Fibroelastic 
  • Situated in the aryepiglottic folds anterior to the corniculate cartilages, may be entirely absent.
Tritiate Cartilage:
  • On occasional,Minute nodule.
  • Located in the posterior margin of the thyrohyoid membrane
Exam Question
  • Cunieform & corniculate cartilage of larynx are elastic in nature
  • Cricoid is the narrowest part of infantile larynx
  • Elastic cartilage are Found in inlet of larynx
  • Cricoid cartilage encircles the larynx
  • Thyroid is a hyaline cartilage
  • The oesophgus commences at lower end of cricoid
  • The narrowest part of trachea in a newborn is at the level of cricoid

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