Head: Larynx Flashcards
Larynx (voice box) function
- Voice production
- Separate food and air
- Guard air passage, maintain patent airway
Cartilages of the larynx
- 9 total
- 3 unpaired
- 3 paired
3 unpaired cartilages of the larynx
- Thyroid
- Cricoid
- Epiglottic
3 paired cartilages of the larynx
- Arytenoid
- Corniculate
- Cuneiform
Thyroid cartilage located at vertebral level
- C4,5
Thyroid cartilage lamina form
- Laryngeal prominence anteriorly (“Adam’s apple”)
- Superior horns
Inferior horns of thyroid cartilage form
- Cricothyroid joint: rotation and gliding movements
Cricoid Cartilage
- Vertebral level C6
- Lamina & arch
Epiglottic cartilage
- Elastic cartilage
- Located at laryngeal inlet
- Thyro-epiglottic and hyo-epiglottic ligaments
Arytenoid cartilages
- Pyramid shaped
- Vocal process
- Muscular process
- Cricoarytenoid joint
Cricoarytenoid joint
allows movement of
- Arytenoid cartilages
Arytenoid cartilages apex attaches to
- Corniculate cartilage
Laryngeal membranes/ligaments
- Thyrohyoid membrane
- Cricothyroid membrane (median and lateral)
- Quadrangular membrane
Thyrohyoid membrane
- Connects thyroid cartilage and hyoid bone
- Pierced by superior laryngeal vessels and internal laryngeal nerve
Median cricothyroid membrane
- Connects cricoid and thyroid cartilages anteriorly
Lateral cricothyroid membrane (conus elasticus)
- Connects cricoid cartilage with thyroid and arytenoid cartilages
- Free superior border forms the vocal ligament
Vocal ligament
- Sound production
- Vocal ligament covered in mucosa: vocal fold
Quadrangular membrane
- Extends between lateral parts of epiglottic and arytenoid cartilages
- Inferior free margin is the vestibular ligament
- The mucosa covered superior margin forms aryepiglottic fold
Vestibular ligament
- Vestibular ligament covered in mucosa: vestibular fold
- Little involvement in sound production
Aryepiglottic fold
- Contributes to lateral boundary of laryngeal inlet
- Corniculate and cuneiform cartilages are embedded within
Laryngeal cavity extends
- From laryngeal inlet (aditus) to cricoid cartilage
Laryngeal cavity contains
- Laryngeal vestibule
- Infraglottic space
- Laryngeal ventricle
- Laryngeal saccule
Laryngeal vestibule is located
- Above the vestibular fold
Infraglottic space is located
- Below vocal folds
Laryngeal ventricle
- Recess between vestibular and vocal folds
Laryngeal saccule
- Blind pocket that opens into the ventricle
- Lined with mucous glands
Glottis (vocal apparatus) contains
- Vocal ligament
- Vocal process
- Rima glottidis
Rima glottidis
- Shape varies and depends on vocal fold position
Extrinsic laryngeal muscles
- Muscles that move the hyoid and larynx
- Infrahyoid Muscles
- Suprahyoid Muscles
Intrinsic laryngeal muscles function
- Alter length and tension of vocal cords
- Alter size of rima glottidis
Intrinsic laryngeal muscles named by
- Attachment
Intrinsic laryngeal muscle innervation
- All innervated by vagus nerve
- Recurrent laryngeal nerve
- External laryngeal nerve
Cricothyroid muscle innervation
- Only intrinsic laryngeal muscle innervated by external laryngeal nerve
Intrinsic laryngeal muscles
- Thyro-arytenoid and vocalis
- Posterior crico-arytenoid
- Lateral crico-arytenoid
- Transverse and oblique arytenoids
- Thyro-epiglottic
- Aryepiglottic
Thyro-epiglottic muscle function
- Affects size of laryngeal inlet
Aryepiglottic muscle function
- Affects size of laryngeal inlet
Cricothyroid muscle function
- Tenses (stretches) vocal ligament
Transverse arytenoid muscle function
- Adducts arytenoid cartilages
Oblique arytenoid muscle function
- Adducts arytenoid cartilage
Posterior crico-arytenoid muscle function
- Abducts vocal folds
Thyro-arytenoid muscle function
- Relaxes vocal ligament
Lateral crico-arytenoid muscle function
- Adducts vocal folds
Arteries of the larynx
- Superior laryngeal artery
- Inferior laryngeal artery
Superior laryngeal artery
- Branch of superior thyroid artery
Inferior laryngeal artery
- Branch of inferior thyroid artery
Veins of the larynx
- Similar to the arteries in name and pattern
- Drain into superior and inferior thyroid vein
Superior laryngeal nerve branches
- External laryngeal nerve
- Internal laryngeal nerve
- Recurrent (inferior) laryngeal nerve
External laryngeal nerve
- Travels with superior thyroid artery
- Innervation: motor cricothyroid muscle
Internal laryngeal nerve
- Travels with superior laryngeal artery
- Innervation: sensory to laryngeal mucosa above vocal folds
Injury to superior laryngeal nerve
- Anesthesia of mucosa above vocal folds
- Impaired ability to change tension of vocal fold
Recurrent (inferior) laryngeal nerve
- Travels near inferior thyroid and inferior laryngeal artery
- Innervates all laryngeal muscles (except 1)
- Sensory to laryngeal mucosa below vocal folds (infraglottic cavity)
Injury to recurrent laryngeal (inferior laryngeal nerve)
- Neck/thyroid surgery
- Sensory loss below vocal folds
- Altered voice
Hyoid bone vertebral level
- C3
Thyroid cartilage vertebral level
- C4,5
Cricoid cartilage level
- C6
- Junction of larynx and trachea
- Junction pharynx and esophagus