Muscles Flashcards
What does the orbicularis oris do?
split into 2:
orbital and palpebral part
orbital closes eyelids
palpebral closes eyelids forcefully
What are the muscles of facial expression?
orbicularis oris oricularis oculi frontalis nasalis buccinator platysma mentalis depressor anguli oris levator labii superioris
what does the orbicularis oris do?
closes and protrudes the mouth
what does the frontalis muscle do?
wrinkles the forehead
elevates eyebrows and forehead
what does the nasalis do?
draws the ala toward the septum to compress the opening
what does the levator labi superioris do?
dilates nostril
elevates lip
raises the angle of the mouth
what does the platysma do?
depresses the mandible
tenses the skin of lower face and neck
what does the mentalis do?
elevates and protrudes the lower lip and wrinkles the chin
what does the buccinator do?
presses against the cheek of molars which assists in chewing
what nerve innervates the muscles of facial expression?
the facial nerve - CN VII
what pharyngeal arch do the muscles of facial expression come from?
second
what condition is it where the muscles of facial expression are drooped on one side?
Bell’s palsy
what do patients with Bell’s palsy present with?
either of the following: not be able to frown not be able to wrinkle forehead unable to close eyes tight unable to smile unable to purse lips unable to tense skin on neck
what are the extraoccular muscles?
superior oblique lateral rectus superior rectus inferior rectus inferior oblique medial rectus
what muscles are not innervated by occulomotor?
lateral rectus
superior oblique
what nerve innervates the lateral rectus muscle?
CN VI - abducens
what nerve innervates the superior oblique muscle?
CN IV - trochlear
what does the levator palpebrae superioris do?
elevates the eyelid
what does the superior rectus do?
elevates, abducts and rotates eyeball medially
what does the inferior rectus muscle do?
depresses, adducts and rotates eye medially
what does the medial rectus muscle do?
adducts eyeball
what does the lateral rectus do?
abducts eyeball
what does the superior oblique do?
medially rotates
depresses
abducts eyeball
what does the inferior oblique do?
laterally rotates
elevates
abducts eyeball
what are the intrinsic muscles of the eye?
smooth muscles that affect the size of the pupil or the shape of the lens for accomodation
what is pure abduction formed by?
lateral rectus
what is pure adduction performed by?
medial rectus
what 3 work together to abduct eye?
SR
LR
IR
what 3 work together to adduct?
IO
MR
SO
what 2 muscles elevate eyeball?
SR
IO
what 2 muscles depress the eyeball?
IR
SO
what is the space of the eye called?
palpebral fissure
what action is superior oblique said to do?
reading a book
looking inwards and downwards
what are the muscles of masstication?
lateral pterygoids
medial pterygoids
temporalis
masseter
what does the temporalis do?
elevates mandible
posterior fibres retrude mandible
what does the masseter do?
elevates and protrudes the mandible
what does the lateral pterygoid do?
protrudes mandible and depresses the chin
can produce side to side movements
what does the medial pterygoid do?
elevates the mandible
protrudes mandible
protrudes the side of the jaw
produces a griding motion
what does tetanus of the masseter lead to?
lockjaw
what is tetanus caused by?
clostridium tetani
what do the muscles of the neck do?
position larynx during swallowing
stabilise the hyoid bone
move head and upper limb
what are the infrahyoid muscles called?
strap muscles
what are the suprahyoid muscles?
geniohyoid
mylohyoid
digastric
stylohyoid
what are the infrahyoid muscles?
sternohyoid
omoyhoid
thyrohyoid
sternothyroid
what are the triangles in the neck?
anterior posterior muscular carotid submandibular submental
what are the borders of the anterior triangle?
line of the neck
scm anterior border
mandible
what are the borders of the posterior triangle?
posterior scm
trapezius
clavicle
what are the 3 fascial layers?
pretracheal
prevertebral
investing
what is the clinical significance of the fascial layers?
infections can spread by this route as theyre compartments
compression
tumour growth
what does the investing layers do?
surrounds the neck and invests the trapezius and scm
what does the pretracheal layer do?
limited to the anterior neck
invests the infrahyoid muscles, thyroid, trachea and oesophagus
what does the prevertebral fascia do?
invests the prevertebral muscles and the vertebral column
what does the carotid sheath enclose?
common carotid artery
IVJ
vagus nerve
