scalp and muscles of facial expression Flashcards
scalp extends between:
- superior nuchal lines posteriorly
- supra-orbital margins anteriorly
- superior temporal lines laterally
5 layers of scalp
skin connective tissue aponeurosis loose connective tissue pericranium
the subarachnoid space is filled with —-
CSF
contains many sweat and sebaceous glands and hair follicles
skin
contains blood vessels and cutaneous nerves
connective tissue
aponeurosis
(epicranial aponeurosis)
tendinous sheet provides attachment for occipitofrontalis muscle and superior auricular muscles
-collectively, constitute the musculo-aponeurotic epicranius
loose areolar tissue
potential spaces that may distend with fluid as a result of injury or infection
- allows free movement of the scalp proper (the first three layers) over the underlying calvaria
- *-contains emissary veins
pericranium
forms the external periosteum of the neurocranium and continuous with the fibrous tissue in the cranial sutures
occipital and frontal bellies of the occipitofrontalis (epicranius) share a common tendon, the _____
epicranial aponeurosis
two bellies of the occipitofrontalis
- frontal belly: does not have bony attachment, protracts the scalp
- occipital belly: arises from superior nuchal line, retracts the scalp
acting simultaneously, the occipital and frontal bellies of the occipitofrontalis elevate the eyebrows and produce what expression?
surprised look
all parts of the epicranius are innervated by the _____
facial nerve
area of the scalp located between the superior temporal line and zygomatic arch and contains the temporalis muscle and fascia
temporal fossa
layers of the temporal fossa
- skin
- subcutaneous tissue
- temporopatietal fascia
- loose areolar tissue
- superficial layer and deep layer of deep temporal fascia
- temporalis muscle
- pericranium
- skull
why does injury of the scalp cause significant bleeding and rapid healing?
scalp is highly vascular with remarkable anastomses
why scalp trauma that involves the epicranial aponeurosis cause wide gap?
epicranial aponeurosis is under tension by the occipitaofrontalis
why does infection of the scalp spread only anteriorly and not laterally or posteriorly?
epicranial aponeurosis has bone attachment posterioly and laterally but not anteriorly
why is the loose areolar tissue (supaneurotic space) a dangerous space?
has the emissary veins which transmit infection to the cranial cavity thru skull foramina e.g. parietal and mastoid foramina
what is black eye (peri-orbital ecchymosis)?
- eccymosis (purple patches) develop bc of extravasatioon of blood into subcutaneous tissue and skin of eyelids and surrounding regions
- results from injury to scalp and/or forehead due to absence of bony attachment of frontal belly or apoenurosis
____ usually occurs following delivery and injury and head trauma
scalp hematoma
caput succedameum
subcutaneous hematoma, crosses temporal and nuchal lines and can cause blue eye
subgaleal hematoma
- hematoma within potential space between the galea aponeurosis and skull periosteum
- crosses over the sutures and limited laterally by the superior temporal line and posteriorly by the superior nuchal line
cephalhematoma
subperiosteal and therefore bound by the suture line (localized to a specific bone)
boundaries of the face
extends superiorly to hair line, inferiorly to chin and base of mandible and on each side to auricle
-forehead is common to both scalp and face
common features of facial muscles
- subcutaneous
- bony origin and pull on skin
- develop from mesoderm in second pharyngeal arch
- arranged around facial orifices to serve as sphincter and dilator for specific facial expressions
- intermingled
- supplied by facial nerve
orbicularis oris
- encircles the mouth within lips (intrinsic)
- continue with surrounding muscles (extrinsic)
- function: sphincter of mouth closes or purses lips; important during articulation
buccinator (L. trumpeter) origin
upper fibers: alveolar process of maxilla opposite molar teeth
lower fibers: alveolar process of mandible opposite molar teeth
middle fibers: from petrygomandibular raphe
insertion of buccinator
upper: into upper lip
lower: into lower lip
middle: decussate so upper fibers into lower lip and upper into upper lip (modiolus)
action of buccinator
smiling, chewing, speech
- prevents accum of food into vestibule
- prevents tilting of teeth in outward direction
- resists distention (when blowing)
- speech
paralysis of buccinator and orbicularis oris causes
- protrusive teeth
- accum of food
- drooling
- slurred speech
3 parts of orbicularis oculi
- palpebral: from medial palp ligament (MPL) and extends within eyelids–gently closes eyes
- lacrimal part: from lacrimal bone and continues thru eyelid–drainage of tears from lacrimal gland laterally to lacrimal sac medially
- orbital part: from MPL overlying orbital margin–tightly closes eyelids to protect eyeballs
when all three parts of the orbicularis oculi contract–
the eyes are fimly closed
corrugator supercilii
- origin: medial end of superciliary arch
- insertion: skin superior to middle of supra-orbital margin and superciliary arch
- action: draws eyebrow medially and inferiorly, creating vertical wrinkles above nose
procerus
- origin: fascia aponeurosis covering nasal bone and lateral nasal cartilage
- insertion: skin of inferior forehead, between eyebrows
- action: depresses medial end of eyebrow; wrinkles skin over dorsum of nose (conveying dislike)
risorius
smile widely
- origin: parotid fascia and buccal skin (highly variable)
- insertion: angle of the mouth
- action: parts of dilators of mouth; smile widely
what makes up the quadratus labii muscle
levator labii superioris alaque nasi
levator labii superioris
zygomaticus minor
levator labii superioris alaque nasi
medial fibers of quadratus labii
- arise from upper part of frontal process of maxilla and passing obliquely downward and lateralward divides into two slips to upper lip and nasal cartilage
- action: raises upper lip and widens nostril
levator labii superioris
intermediate of quadratus
- arises from lower margin of orbit immediately above the infraorbital foramen and inserted into upper lip
- action: raises upper lip, depends nasolabial fold (sadness)
zygomaticus minor
lateral fibers of quadratus
- arises from anterior part of zygomatic bone and inserted in the lateral part of upper lip
- action: raises upper lip
zygomaticus major
- origin: lateral aspect of zygomatic bone
- insertion: angle of mouth (modiolus)
- action: elevate lip – bilaterally to smiale unilaterally to sneer
levator anguli oris
-origin: infra-orbital maxilla (canine fossa)
-insertion: angle of mouth
-action: raises angle of mouth
(caninus)
canine space
- infra-orbital space
- thin potential space on face
- located between the levator anguli oris muscle inferiorly and levator labii superiors superiorly
depressor anguli oris (triangularis)
- origin: anterolateral base of mandible
- insertion: angle of the mouth
- action: lowers angle of mouth
- acts bilaterally to frown
depressor labii inferioris
- origin: platysma and anterolateral body of mandible
- insertion: skin of lower lip
- action: part of dilators of mouth; depresses and everts lower lip (sadness)
mentalis
- origin: body of mandible (anterior to roots of inferior incisors)
- insertion: skin of the chin
- action: raises chin, protrudes lower lip, decreases depth of lower vestibule
witches chin
- complete reflection of mentalis muscle for purpose of extension of subperiosteal implant
- -failure of mentalis reattacment
platysma
- origin: fascia covering chest wall (subcut tissue of infra-clavicular and supraclavicular regions)
- insertion: lower border of mand and angle of mouth
- action: raises skin of neck and lowers corner of mouth. Also depresses mandible
