Larynx- Controlling Airways & Noise Flashcards
what are the extrinsic muscles of the larynx
- thyrohyoid muscle
- cricothyroid muscle
- sternothyroid muscle
- sternohyoid muscle
- sternocephalic muscle
which muscles move the larynx caudally
- thyrohyoid m
- sternohyoid m
- sternothyroid m
which muscles move the pharynx, tongue and hyoid apparatus rostrally
- geniohyoid muscle
- hypoglossus muscle
what are the muscles shown
what are the muscles of the pharynx, tongue and hyoid apparatus innervated by
hypoglossal nerve (XII)
what are the ventral muscles of the neck innervated by
ventral branch of cervical spinal nerve and accessory nerve (XI)
what is the function of the larynx
controls the amount of air entering lower respiratory passageways and closes the larynx during swallowing
does this by altering the position of the vocal processes (arytenoid) and folds
what are the instrinsic muscles of the larynx
- dorsal cricoarytenoid m
- transverse arytenoid m
- cricothyroid m
- lateral cricoarytenoid m
- thyroarytenoid m
what is the function of dorsal cricoarytenoid m and what nerve innervates it
abductor
opens the glottis
innervated by caudal recurrent laryngeal nerve (branch of vagus nerve X)
what is the function of transverse arytenoid muscle and what innervates it
adductor –> closes the glottis, pulls arytenoid cartilages together
innervated by caudal (recurrent) laryngeal nerve (branch of vagus)
what is the function of the lateral cricoarytenoid muscle and what does it innervate
adducts the vocal process of the arytenoid cartilages –> closes the glottis
innervated by caudal (recurent) laryngeal nerve
what is the function of thyroarytenoid muscle
adjust tension in vocal folds (fine adjustment)
innervated by caudal (recurrent) laryngeal nerve
what does the thyroarytenoid muscle split into in the dog and horse
splits into ventricularis and vocal muscle
what does the lateral ventricle in the dog responsible for
barking
what are the intrinsic muscles shown
what intrinsic muscles are shown
red: dorsal cricoarytenoid m
blue: transverse arytenoid m
what intrinsic muscle is this
cricothyroid m
what intrinsic muscle is shown
lateral cricoarytenoid m
lateral wall of the thyroid cartilage has been removed to reveal the lateral cricoarytenoid musles
what intrinsic muscle is shown
thyroarytenoid mm
lateral wall thyroid cartilage has been removed to reveal the thyroarytenoid muscle (splits in horses, dogs and pigs)
complete this chart
what is the blood supply to the laryngeal region
cranial and caudal laryngeal artery (branch of common carotid artery)
satellite veins drain
what is the lymphatic drainage of the laryngeal region
retro-pharyngeal lymph nodes
what occurs to the larynx during swallowing
- bolus formed in oral cavity
- pushed into oropharynx by tongue (voluntary)
- soft palate elevated to close off nasopharynx
- bolus moved thru pharynx into esophagus by sequential contraction of constrictor muscles while larynx and hyoid apparatus are moved rostrally
- epiglottis partially covers aditus
- glottis closed by lateral cricoarytenoid mm/transverse arytenoid mm
- bolus passes over or around epiglottis
if food doesn’t enter –> contact with mucosa of vestibule initiates reflex coughing
how does the larynx lead to vocalization
narrowing and widening to glottis causes air to vibrate the vocal folds
pitch –> length and tension of vocal folds, action of cricothyroid mm/thyroarytenoid mm
resonance –> other cavities of the head (paranasal sinuses)
what are clinical problems associated with larynx in horses
- soft palate displacement
- aryepiglottic fold entrapment
- left recurrent laryngeal neuropathy (hemiplegia)
what is soft palate displacement
dislocation of larynx and trapping of epiglottis below soft palate (chocking up-gurgling)
corrected by removing epiglottis
what is aryepiglottic fold entrapment
folds partially covers entrance to glottis
what is left recurrent laryngeal neuropathy in horses
degeneration of left recurrent laryngeal nerve
results in paralysis of left dorsal cricoarytenoid muscle (abductor) –> vocal fold becomes flaccid
how is left recurrent laryngeal neuropathy corrected
prosthesis, removal of lateral ventricle
what are clinical problems associated with larynx in dogs
- elongation of soft palate
- fractures of larynx and hyoid
- paralysis of larynx (older dogs, inherited in some cases)
what is the shape of epiglottis is ruminants
epiglottis –> rounded
what is the shape of the vestibule in ruminants
short and deep vestibule
what is the features of the interior in the ruminants
smooth
are there vestibular folds/lateral ventricles/cuneiform processes in ruminants
no
is the glottis wide or narrow in ruminants
narrow
what is the shape of the vestibule in pigs
long and narrow
what is the shape of epiglottis in pigs
large round apex
what is the feature of the arytenoid cartilage in pigs
bifid corniculate process
are there lateral ventricles in the pig
yes
is the median recess present in pigs
yes
what is the shape of the epiglottis in horses
pointed
are there corniculate processes on the arytenoids in horses
yes
they are prominant
do horses have lateral ventricles and a median recess
yes
what is good access for surgery in horse larynx
thyroid notch is large
what is assocaited with epiglottis in horses
cuneiform processes
what species is this
ruminant
what species is this
pig
what species is this
horse
