Larynx and Trachea

Larynx

• Voice production

• Maintaining patent airway

• Connects pharynx and trachea

C3-C6

Location of larynx

Epiglottis, thyroid, cricoid

Unpaired cartilages of the larynx

Cuneiform, corniculate, arytenoid

Paired cartilages of the larynx

Laryngeal prominence

Adam’s apple

Cricothyroid joint

• Rotation and gliding of the thyroid cartilage

• Changes in the length of the vocal folds

Cricoid cartilage

Level of C6 vertebra where:

• carotid artery can be compressed

• larynx and trachea join

• pharynx joins esophagus

• recurrent laryngeal nerve

• only complete ring of cartilage

Arytenoid cartilage

• Paired pyramidal cartilages

• Articulate with superior border of cricoid

Cricoarytenoid joint

• Slide toward or away from each other

• Tilt anteriorly and posteriorly

• Rotate

Conus elasticus

aka vocal ligament

Epiglottic cartilage

• Posterior to the root of the tongue

• Anterior to laryngeal inlet

• Superior part of the anterior wall

• Superior margin of the inlet

Epiglottic cartilage

Elastic cartilage that functions as a valve that closes of larynx during swallowing

Laryngeal inlet

• Communicates with the laryngeopharynx

• Level of the inferior border of cricoid

Laryngeal vestibule

Laryngeal inlet to vestibular folds

Middle part of the laryngeal cavity

Vestibular fold to vocal fold

Infraglottic cavity

Vocal fold to inferior border of cricoid

Laryngeal saccule

Lined with mucosal glands

Vocal folds

Produce audible vibrations when free margins are closed and air is pushed out of our lungs

Rima glottidis

The V-shaped opening formed between the true vocal cords, which permits the passage of air through the larynx

Narrow and wedge-shaped

Shape of rima glottidis during normal breathing

Wide and trapezoidal

Shape of rima glottidis during forced expiration

Slit-like

Shape of rima glottidis during phonation

Extrinsic muscles

Muscles that move larynx as a whole

• Infrahyoid muscles (depress hyoid and larynx)

• Suprahyoid muscles (elevate hyoid and larynx)

Intrinsic muscles

Muscles that alter length and shape of vocal folds and rima glottides

• Abductors and Adductors

• Sphincters

• Tensors and Relaxers

Adductors

Lateral Cricoarytenoid Muscles and Transverse and Oblique Arytenoid are (?)

Lateral cricoarytenoid muscles

• Pull muscular processes anteriorly

• Rotate anterior cartilages

Transverse and oblique arytenoid

• Arise from one arytenoid and inserts to contralateral arytenoid

• Pulls arytenoid cartilages together

Abductor

Posterior cricoarytenoid is an (?) muscle

Posterior cricoarytenoid

• Arise from cricoid cartilage lamina and inserts into vocal process of arytenoid

• Rotate vocal processes laterally

Tensor

Cricothyroid muscle is a (?) muscle

Cricothyroid muscle

• Arise from the anterolateral part of the insert into the inferior margin and inferior horn of the thyroid cartilage

• Tilt or pull the thyroid cartilage anteriorly and inferiorly

• Vocal ligaments elongates and tightens

• Raise pitch of voice

Relaxer

Thyroarytenoid muscles are (?) muscles

Thyroarytenoid muscles

• Arise from the lower half of the posterior aspect of the thyroid cartilage and cricothyroid ligament and insert into the anterolateral arytenoid surface

• Pull arytenoid cartilages anteriorly

• Lower the pitch of the voice

Tensor and Relaxer

Vocalis muscle is a (?) muscle

Vocalis muscle

• Lateral to the vocal ligaments

• Origin: Lateral surface of the vocal process of arytenoid

• Insertion: Ipsilateral vocal ligament

• Acts during animated speech and singing by tensing and relaxing the vocal ligaments

Recurrent laryngeal nerve

Innervation of all laryngeal muscles except cricothyroid muscles

External laryngeal nerve

Innervation of cricothyroid muscles

Superior laryngeal artery

Blood supply of the internal surface of larynx

Inferior laryngeal artery

Blood supply of mucous membrane and muscles of inferior part of larynx

Internal jugular vein

The superior thyroid vein drains into the (?)

Brachiocephalic vein

The inferior thyroid vein drains into the (?)

Internal laryngeal nerve

• Runs with superior laryngeal artery

• Supplies:

  • Sensory fibers to laryngeal mucous membrane of vestibule and middle laryngeal cavity

  • Superior surface of vocal cords

External laryngeal nerve

• Posterior to sternothyroid muscle with superior thyroid artery

• Supplies:

  • Cricothyroid muscle

  • Motor fibers

Inferior laryngeal nerve

• Continuation of recurrent laryngeal nerve

• Motor innervation to larynx

• Sensory innervation to mucosa of infraglottic cavity

Trachea

• Starts at inferior end of larynx (C6)

• Ends at sternal angle (T4-T5)

• Terminates into right and left bronchi

Tracheal cartilage

• Incomplete cartilaginous ring

• Deficient posteriorly