The Larynx Flashcards
2 types of laryngeal musculature
INTRINSIC Musculature - interconnects cartilages of the larynx
EXTRINSIC Musculature - connects larynx to other surrounding structures, e.g. Sternum, hyoid bone, mastoid process, etc. (STRAP MUSCLES)
Name the 4 main cartilages of the larynx
Cricoid
Thyroid
Epiglottis
Arytenoids
List Larynx’s 5 Intrinsic Muscles
Thyroarytenoid muscle -
2 parts:
Vocalis - medial tensing (helps with pitch control)
Thyromuscularis - quick shortening
Cricothyroid muscle
2 parts:
Pars recta -
Pars oblique - extends to inferior cornu of thyroid
Lateral cricoarytenoids
Posterior cricoarytenoids
Interarytenoid
Thyroarytenoid muscle
Attached below thyroid notch
Attachment is called Anterior Commissure
Theoretically divided into 2 parts:
Vocalis - medial tensing (helps with pitch control)
Thyromuscularis - quick shortening
Cricothyroid muscle
Stretches vocal folds
Originates at anterior arch of cricoid
Main pitch control - elevates cricoid arch, depresses thyroid lamina
2 parts (pars recta & pars oblique)
Cricoarytenoid muscles
Lateral cricoarytenoids - primary adductor
Closes from vocal processes to anterior commissure
Posterior cricoarytenoids - primary abductor
Interarytenoid Muscle
connects 2 arytenoids
Aids Lateral cricoarytenoid muscle - closes posterior glottis
2 fiber directions
Transverse (==)
Oblique (X)
Extrinsic Musculature
2 main groups: elevators and depressors
Act as suspensory mechanism (elastic scaffolding)
Another division: supra-hyoid (above) & infra-hyoid (below)
5 Depressors
Sternothyroid -primary or direct depressor
Sternohyoid - secondary or indirect depressor (can compress tissue between thyroid and hyoid)
Omohyoid - depresses and retracts hyoid (runs from scapula to hyoid)
Cricopharyngeus - lower sides of cricoid to junction of pharynx and esophagus (May widen lower pharynx)
Trachea - exerts gravitational pull as diaphragm descends (aka Tracheal Pull)
2 False elevators
Digastric - 2 sections
Anterior - chin to hyoid (retracts mandible)
Posterior - hyoid to mastoid process (elevates hyoid)
Stylohyoid - elevates and retracts hyoid (hence, the larynx)
6 Elevators
Mylohyoid & Hyoglossus - hyoid bone to tongue
Geniohyoid - mental spine (chin) to hyoid
Genioglossus - mental spine (chin) to lower surface of tongue and hyoid
Both genioglossus and Hyoglossus move hyoid bone and thyroid cartilage forward which stretches the vocal folds (important for higher frequencies)
Stylopharyngeus - styoid process (behind jaw) to palatopharyngeus to superior Cornu of thyroid
dilates and elevates pharynx/ tilts thyroid forward
Helps both with glottal closure and maximum vocal fold elongation
Essential for optimal high voice production
Thyrohyoid - either depressor or elevator (elevates larynx or depresses hyoid)
Innervation
connection btw brain and body by means of the central nervous system
Vagus nerve (10th cranial nerve)
Vagus nerve (10th cranial nerve) - longest and most complex of cranial nerves
Leaves brain and skull through same opening as jugular vein - winds through neck into thorax and upper abdomen
Two branches of vagus nerve innervate larynx:
Two branches of vagus nerve innervate larynx:
Superior laryngeal nerve - leaves vagus just about larynx
2 branches:
Internal - enters through thyrohyoid membrane (supplies laryngeal mucosa (detects foreign objects/tickle sensation))
External - motor nerve - descends behind Sternothyroid muscle (supplies cricothyroid muscle)
Recurrent Laryngeal Nerve - motor nerve
Leaves vagus well below larynx in upper thorax
Supplies remaining laryngeal muscles
2 branches: left & right
Left Side–significantly longer
Nervous signals arrive first to right side (only slight delay)
May be linked w/ vibrato
2 layer scheme of vocal fold soft tissue
- Cover: epithelium, superficial layer, intermediate later
2. Body: deep layer, muscle
5 layer scheme of vocal fold soft tissue
From outside in:
- Epithelium
- Superficial layer
- Intermediate layer
- Deep layer
- Muscle
3 layer scheme of vocal fold soft tissue
- Mucosa (epithelium & superficial layer)
- Ligament (intermediate layer & deep layer)
- Muscle (muscle)
Bundles of muscle tissue
Muscle fascicles
Hyaluronic acid
Acid present in vocal folds helping protect from impact
More present in male than female
Epithelium
.05-.1mm Stratified squamous (layered, scale-like)
3 layers of the lamina propria, their thickness and composition
Superficial (.5mm), elastin
Intermediate, primarily elastin, also some collagen
Deep, collagen
Intermediate + Deep = 1-2mm
Thickness of thyroarytenoid muscle (vocalis)
7-8mm
Quadrangular membrane
Secretes lube for the vocal folds
2 parts of thyroarytenoid muscle
Vocalis - medial tensing (helps with pitch control)
Thyromuscularis - quick shortening
Attachment of the thyroarytenoid muscle is called?
Anterior commisure
Nerve branch that serves the cricothyroid muscle
External branch of the superior laryngeal nerve
2 parts of cricothyroid muscle
Pars recta - extends to lower border of thyroid lamina
Pars oblique - extends to inferior cornu of thyroid
Scalene muscles
cervical spine to 1st two ribs
Postural and serves respiratory function by helping to elevate upper thorax.
What are false elevators?
muscles whose use produces excess tongue and pharyngeal tension
2 chest voice conditions
Very small longitudinal tension
Very little elongation of the vocal folds
2 chest voice characteristics
Slack vocal ligaments
Thick vocal folds
3 chest voice characteristics
Large amplitudes (glottis opens widely between vibrations)
Firm glottal closure
Vertical phase differences (opens and closes at bottom first, followed by top)
2 falsetto voice conditions
Great longitudinal tension and medial compression
Great elongation of the vocal folds
2 falsetto voice consequences
Tense vocal ligaments
Thin vocal folds
3 falsetto voice characteristics
Small amplitudes
Imperfect glottal closure
Negligible vertical phase differences
2 sections of the digastric muscle
Anterior - chin to hyoid (retracts mandible)
Posterior - hyoid to mastoid process (elevates hyoid)
Primary or direct depressor
Sternothyroid
Secondary or indirect depressor (can compress tissue between thyroid and hyoid)
Sternohyoid
Elevator muscle that helps both with glottal closure and maximum vocal fold elongation
Essential for optimal high voice production
Stylopharyngeus
Describe thyroid cartilage
2 plates fused together/shaped like a shield
Inferior Cornu - joined flexibly to cricoid
Superior Cornu - loosely jointed with hyoid bone
Adam’s apple or thyroid notch - apex
Describe arytenoid cartilages
2 triangular pyramids resting on upper edge on back of cricoid
Glide medially and laterally, rotate, glide anteriorly and posteriorly
Vocal process and muscular process
Corniculate cartilage at top of structure
Describe the epiglottis
Very elastic, cartilaginous material
Shaped like leaf or tongue of a shoe
Attaches just above the vocal folds (anterior of the thyroid cartilage)
Pulled down during swallowing by Aryepiglottic folds and back of tongue
Describe the cricoid cartilage
shaped like a signet ring/sits on top of the trachea
False Vocal Folds
Ventricular Folds
Primary purpose is to assist vocal folds in closing the airway
Difficult to control, not much muscle fiber
Upper border of Ventricles of morgagni and below them is glands secreting lube onto vocal folds
Describe the hyoid bone
Horseshoe shaped bone located above the thyroid
Connected to thyroid by the thyroid membrane
Only free floating bone in the body
Suspended by the strap muscles
