Functional Anatomy of Phonation Flashcards
Laryngeal “Skeleton” Cartilages
- cartilages (9)
- 3 unpaired
- thryoid (hyaline)
- cricoid (hyaline)
- epiglottis (elastic)
- 6 paired
- arytenoid (elastic)
- corniculate (elastic)
- cuneiform (elastic)
- 3 unpaired
Thyroid cartilage (shape, type, location, connected by)
- Shield-shaped
- Hyaline cartilage
- Lies at vertebral level C4-C6
- Thryoid (laryngeal) prominence
- Articulates with cricoid cartilage
- Connected to hyoid by thryohyoid membrane (lig.)
- Connect to cricoid by cricothyroid membrane (lig.)
Cricoid cartilage
ring shaped
hyaline cartilage
articulates with arytenoid and thryoid cartilages
arytenoid cartilage
- funnel-shaped
- elastic cartilage
- articulates with cricoid cartilage at base
- muscular process
- vocal process: attachment for vocal ligaments
- apex articulates with corniculate cartilage
Cricothyroid joint
- pivot movements of thyroid cartilage
Cricoarytenoid joint
rotational and sliding movements of arytenoid cartilages
Epiglottis: Aryepiglottic fold
- muscles that close the laryngeal aditus (opening)
- aryepiglottis m.
- thryoepiglottic m.
- innervated by RLN (CN X)
- corniculate and cuneiform cartilages
- used in the “vocal growl” in jazz and death metal music
Vocal anatomy
- vocal ligament: runs from arytenoid to thyroid cartilages
- vocal folds: vocal ligaments, vocalis and thyroarytenoid mm.
- vestibular folds: AKA false vocal folds, contain ventricular ligament
- glottis: vocal folds and rima glottidis (opening b/w the folds)
Laryngeal muscles: functional groups
- Abduction of vocal folds
- rotation: posterior cricoarytenoid m.
- Adduction of vocal folds
- rotation: lateral cricoarytenoid m.
- sliding: transverse arytenoid m., oblique arytenoid m.
- Relaxes vocal folds (low pitch)
- thyroarytenoid m. and vocalis m.
- Tenses vocal folds (high pitch)
- cricothyroid m. rotates anterior thyroid cartilage inferiorly
Laryngeal muscles: Posterior cricoarytenoid
- Abducts vocal folds
- RLN, CN X (SVE)
example: forced respiration
Laryngeal muscles: Lateral cricoarytenoid
- adducts vocal folds
- RLN, CN X (SVE)
Laryngeal muscles: transverse arytenoid
- adducts vocal folds
- RLN, CN X (SVE)
Laryngeal muscles: oblique arytenoid
- adducts vocal folds
- RLN, CN X (SVE)
Laryngeal muscles: thryoarytenoid
- relaxes vocal folds
- RLN, CN X (SVE)
Laryngeal muscles: vocalis
- relaxes vocal folds
- RLN, CN X (SVE)
example: lowers pitch of voice
Laryngeal muscles: cricothyroid
- tenses vocal folds
- external branch, SLN, CN X (SVE)
example: increases pitch of voice
Control of vocal pitch
- pitch is determined by rate of vibration
- thickness and length of the vocal folds
- thicker, longer folds=lower pitch
- these changes occur during puberty in males
- tension of the vocal folds
- increased tension=tighter=higher pitch
- Rima glottidis (opening b/w folds) is narrow
- decreased tension=looser=lower pitch
- Rima glottidis is wide
- increased tension=tighter=higher pitch
Innervation of the Larynx
- CN X: Vagus n.
- Superior laryngeal n. (SLN)
- internal branch: viscerosensory (GVA) to mucosa above the vocal folds
- pierces thyrohyoid membrane
- external branch (SVE) to cricothyroid m.
- internal branch: viscerosensory (GVA) to mucosa above the vocal folds
- Recurrent laryngeal n. (RLN)
- intrinsic mm. (SVE): lateral and posterior cricoarytenoid mm., transverse and oblique arytenoid mm., thyroarytenoid m., vocalis m.
- Viscerosensory (GVA) to mucosa below the vocal folds
- Superior laryngeal n. (SLN)
Recurrent laryngeal nerve palsy
- Common causes
- thyroid biopsy
- compression at aortic arch or thoracic outlet (e.g. tumor)
- aortic aneurism
- Common signs
- dyphonia (hoarseness) or aphonia (voice loss)
- dyspnea (trouble breathing) due to paralysis of posterior cricoarytenoid muscle
