Larynx & hyoid apparatus Flashcards
what is the larynx
cartilaginous tube at the base of the throat acting as a valve, sound maker and pressure control
describe the location of the larynx
- ventral to the laryngopharynx (start of the esophagus)
- caudal to the tongue
- suspended by the hyoid apparatus
- easily palpable caudal to the jaw
- in horses and ruminant, between the rami of the mandible
- in carnivores and pigs, in the neck
describe the orientation of structures surrounding the larynx
what are the functions of the larynx
- connection of nasal part of pharynx and trachea
- breathing/respiration
- protection of lower airways
- swallowing
- straining
- coughing
- formation of voice, phonation
describe the fixation of the hyoid
- suspended by the hyoid bones which articulate with the base of the skull (temporal bone)
- linked by synovial joints or cartilagenous joints
why is the hyoid different in the horse than the dog and why is it significant
in the horse, the stylahyoid is very large and has no mechanical joint with the epihyoid (epihyoid is vestigial)
this makes it so that the hyoid is less able to swing back and forth
list the bones of the hyoid in order of how they articulate from the temporal bone to the trachea
- typanohyoid bone
- stylohyoid bone
- epihyoid (vestigial in horses)
- ceratohyoid
- basihyoid (unparied)
- thyrohyoid
mnemonic: today someone erupted come before ten
list the tissues present in the larynx
- hyaline and elastic cartilage (skeleton of the larynx)
- collagenous and elastic ligaments
- striated musculature
- mucous membrane
- vessels
- nerves
What is the function of the hyoid apparatus
Holds the larynx in place and supports the pharynx and tongue from the skull.
describe the divisions of the laryngeal cavity
red: Cavity of the Larynx: hourglass shape.
ntrance to the larynx-Vestibule medianus recess (horse, pig)
green: Glottis lateral ventricle, describes hole, arytenoid cartilage is seal (dog, horse, pig), glottic cleft
purple: Infraglottic cavity
label theanatomy seen in a endoscopic view
what structure provides the major seal of the larynx
the vocal folds
Describe what makes up the mucosa of the larynx and where it is found
Mucosa = Epithelium + Lamina propria
Stratified squamous at the entrance (epiglottis) and on the folds-
solid food passing over. Other areas: pseudostratified ciliated.
Describe the shape and location of the hyaline and elastic cartilages of the larynx
hyaline cartilage
- thyroid: U shaped
- Cricoid: signet ring shaped
- paired arytenoids (also have elastic cartilage: sort of triangular
elastic cartilage
- epiglottis: leaf shaped
what are the palpable landmarks of the larynx
- thyroid cartilage cranio-ventral in the midline
- cricoid cartilage caudoventral
- first cartilage of the trachea