the neck and larynx Flashcards
where is the superficial cervical fascia
lies between dermis and deep cervical fascia
what does the superficial cervical fascia contain
superficial neurovascular structures and lymph nodes
CT especially subcutaneous fat
muscles, namely platysma
what are the 4 layers of deep cervical fascia
investing layer of deep cervical fascia
prevertebral layer of deep CF
pretracheal layer of DCF
carotid sheath
why do we have fascial planes
so muscles contract when theyre meant to
what is investing fascia
most superficial layer of DF
encloses/invests the trapezius and SCM muscles
glands muscles and thickenings of investing fascia
G: parotid, submandibular
M: SCM, trapezius
T: omohyoid, digastric
describe the pre-tracheal layer of fascia
located within the ant. region of the neck
encloses thyroid, trachea and oesophagus
describe the pre-vertebral layer of fascia
forms a tubular sheath which surrounds vertebral column and associated muscles
describe the carotid sheath
surrounds internal jugular vein, common carotid artery and vagus nerve
what are the triangles of the neck
2 main paired triangles divided into smaller paired triangles
content incl. muscles, nerves, arteries, veins, and lymph nodes
describe the digastric triangle
aka submandibular
bounded: sup. by inferior boundary of the mandible
posteriorly by anterior part of posterior belly of digastric
anteriorly by the lateral aspect of the anterior belly of digastric
describe the submental triangle
aka suprahyoid triangle
borders: sup. ant belly of digastric
inf. - body of hyoid bone
ant. by the midline
floor= mylohyoid
function of the mylohyoid muscle
if mandible is fixed in position = elevated hyoid
if hyoid fixed in position = depresses mandible
artery vein and nerves in carotid triangles
common carotid artery - bifurcates into the external and internal carotid arteries
internal jugular jein - responsible for venous drainage of head and neck
cranial nerves - CNVII, CNIX, CNX, CNXI, CNXII
what is the cervical plexus
network of nerves located within the neck. has both motor and sensory branches
describe the development of the larynx
in infants and most nonhuman mammals - epiglottis touches uvula so that there is a respiratory channel from nose -> larynx and 2 lateral swallowing pathways from mouth -> pyriform recesses -> oesophagus
larynx descends during growth separating epiglottis and uvula - common pathway for breathing and swallowing
consequence of developing larynx
cannot swallow and breathe simultaneously
increased risk of choking
louder voice
greater range of sounds
describe the larynx
3 unpaired cartilages
1 bone
3 paired cartilages
describe the thyroid
incomplete posteriorly
forms laryngeal prominence (adam’s apple)
only anchored at two points - can tilt
describe the cricoid
only complete cartilaginous ring around airway
large flat lamina posteriorly and thin arch anteriorly
articulates with inf. horn of thyroid and arytenoids
what is the joint between inf. horn of thyroid and cricoid called
cricothyroid joint
describe the arytenoid
pyramidal shaped with 3 processes:
apex (sup.) -> articulates with corniculate cartilages
muscular process (posterolateral) -> for muscle attachment
vocal process (anterior)-> attachment of a vocal ligament
describe the thyrohyoid membrane
between hyoid and sup. border of thyroid cartilage
holes for entry of nerves/vessels
describe the cricothyroid membrane
dome-shaped membrane attaching to:
sup. border of cricoid (inf)
internal aspect of thyroid (ant.)
vocal processes of arytenoids (post)
describe the quadrangular membrane
paired, attaches to:
lateral border of epiglottic cartilage (ant.); lateral border of arytenoid (post)
2 free borders:
upper=aryepiglottic fold
lower=vestibular ligament (when covered with epithelium = false vocal fold)
what moves the larynx
extrinsic and intrinsic muscles
what do vocal ligaments attach to
internal aspect of thyroid in midline
vocal processes of arytenoids
function of movement of larynx
breathing, prevent entry of food/liquid, valsalva manoeuvre, vibration of vocal ligaments as air passes through rima glottidis allows phonation
function of intrinsic muscles
tilt thyroid ant, and post - stretching/ relaxing vocal ligaments
rotate the arytenoids - moving the vocal ligaments together or apart
describe the cricothyroid muscle
tilts thyroid anteriorly, stretching the ligaments -> increases the pitch of voice
attachment and function of post. and lat. cricoarytenoid muscle
muscular process of arytenoid -> post/lat aspects of cricoid -> rotate arytenoids
post CA-> abduct vocal cords
lat CA -> adducts vocal folds
function of interarytenoid muscles
join arytenoids -> adduct arytenoids closing posterior part of rima glottidis
describe vocalis
attaches along length of vocal ligament and modulates its tension
describe thyroarytenoid
pulls thyroid and arytenoids closer together relaxing vocal ligament and reducing pitch
describe aryepiglotticus
pulls epiglottis inferiorly over laryngeal inlet during swallowing
what innervates the larynx
CNX
