Head and Face Flashcards
scalp
-Strong flexible mass of Skin, Fascia, Muscular tissue
-Highly vascular
-Hair provides insulation
galea aponeurotica
-between scalp and skull
-fibrous connective sheath
subaponeurotica (areolar) tissue
-permits venous blood flow from the dural sinuses to the venous vessels of scalp
-emissary veins- potential route for infection
-abscess, thrombosis of superior sagital sinus, infection, purulent
-laceration to scalp can cause acute blood loss anemia
structures of the scalp
-SCALP
-skin
-connective tissue
-aponeurotica
-layer of areolar tissue
-periosteum of skull
skull bones
-facial bones
-cranium:
-vault fors brain
-strong, light, rigid, spherical bone
-unyielding to increased intracranial pressure (ICP)
-bones:
-frontal
-parietal
-occipital
-temporal
-ethmoid
-sphenoid
skull: foramen magnum
-largest opening of skull
-spinal cord exits
skull: cribriform plate
-inferior aspect (base)
-rough surface
-brain can be easily injured:
-abrasion
-contusion
-laceration
-pt may present with rhinorrhea - CSF -> can cause infection back up to brain
-NO NASAL GASTRIC TUBE WHO HAS BASILAR SKULL FRACUTRE, FACIAL TRAUMA -> worry about putting it through cribriform plate and into brain -> do oral
dura mater
-Layers:
-Outer: Cranium’s inner periosteum
-Inner: Dural layer
-Between: Dural sinuses - Venous drains for brain
-Provides continuous connective tissue
-Forms partial structural divisions:
-Falx cerebri
-Tentorium cerebelli
-Large arteries above- Provide blood flow to the surface of the brain
pia mater
-Closest to brain and spinal cord
-Delicate tissue
-Covers all areas of brain and spinal cord
-Very vascular- Supply superficial areas of brain
arachnoid membrane
-“Spider-like”
-Covers inner dura
-Suspends brain in cranial cavity- Collagen and elastin fibers
-Subarachnoid space beneath- CSF -Cushions brain
CSF
-Clear, colorless fluid
-Comprised of- Water, Protein, Salts
-Cushions CNS
-Made in largest two ventricles of brain
-Medium for nutrients and waste products to diffuse into and out of brain
brain
-Occupies 80% of cranium
-Comprised of 3 major structures:
-Cerebrum
-Cerebellum
-Brainstem
-High metabolic rate
-Receives 15% of cardiac output
-Consumes 20% of body’s oxygen
-Requires constant circulation
-IF blood supply stops:
-Unconscious within 10 seconds
-Death in 4–6 minutes
cerebrum
-Function:
-Center of conscious thought, personality, speech, and motor control
-Visual, auditory, and tactile perception
-Lobes:
-Frontal - Personality
-Parietal- Motor and sensory activity, Memory and emotion
occipital
-sight
temporal
-long term memory
-hearing
-speech
-taste
-smell
cerebrum: flax cerebri
-Divides cerebrum into right and left hemispheres
cerebrum: central sulcus
-Fissure splits cerebrum into right and left hemispheres
-Each hemisphere controls the opposite side of the body
cerebrum: tentorium
-Fibrous sheet within occipital region
-Brainstem perforates through incisura tentorium cerebelli.
-Oculomotor nerve (CN-III) travels along:
-Controls pupil size
-Compression results in pupillary disturbances
-dilated nonreactive pupil with injury
cerebrum: hemispheres
-left- DOMINANT:
-mathematical computations- occipital
-writing- parietal
-language interpretation- occipital
-speech- frontal
-right- NON-DOMINANT
-non verbal imagery
cerebellum
-located under tentorium
-fine tunes motor control
-allows smooth movement balance
-maintenance of muscle tone
brainstem
-Central processing center
-Communication junction among:
-Cerebrum
-Spinal cord
-Cranial nerves
-Cerebellum
-Structures:
-Midbrain
-Pons
-Medulla oblongata
midbrain
-Upper portion of brainstem
-Structures
-Hypothalamus- Endocrine function, vomiting reflex, hunger, thirst, Kidney function, body temperature, emotion
-Thalamus- Switching center between pons and cerebrum
-thalamus is Critical element in Ascending Reticular Activating System (A-RAS) -> ESTABLISHES CONSCIOUSNESS
-thalamus is Major pathways for optic and olfactory nerves
-Associated structures
pons
-communication interchange between cerebellum, cerebrum, midbrain, and spinal cord
-bulb shaped structure above medulla
-sleeping phase of the RAS
medulla oblongata
-bulge in the top of spinal cord
-centers:
-respiratory center- controls depth, rate, and rhythm
-cardiac center- regulates rate and strength of cardia contractions
-vasomotor center- distribution of blood and maintains BP
CNS circulation
-arterial:
-4 major arteries- 2 internal carotid arteries from common carotid AND 2 vertebral arteries
-circle of willis- internal carotids and vertebral arteries -> encircle the base of brain
-venous:
-venous drainage occurs through bridging veins
-bridge dural sinuses
-drain into internal jugular veins
blood brain barrier
-less permeable than elsewhere in body
-DOES NOT allow flow of interstitial proteins
-Reduced lymphatic flow
-Very protected environment
-Blood acts as irritant resulting in cerebral edema
-NO highly charged, large, not lipid soluble can go through
-hepatic disease- fugal flow -> reverse flow ends up into systemic circulation before going through liver -> ammonia -> hepatic encephalopathy
-edema when blood brain barrier abnormal -> irritation of parenchyma -> high ICP
cerebral perfusion pressure
-Pressure within cranium (ICP) resists blood flow and good perfusion to the CNS -> Pressure usually less than 10 mmHg
-Mean Arterial Pressure (MAP): Must be at least 50 mmHg to ensure adequate perfusion
-at least MAP 65 and higher than ICP
-ICP > 20 danger zone
-MAP = DBP + 1/3 Pulse Pressure
-Cerebral Perfusion Pressure (CPP):
-Pressure moving blood through the cranium
-CPP = MAP - ICP
-if ICP is higher than MAP -> we cant perfuse -> anoxia
-go up on MAP or go down on ICP -> better flow
-ex. raise the BP and catheter into ventricle to remove pressure
-rapid increase in ICP - herniation at 60
-pressure on the pons
CCP and MAP calculation ex
-BP = 100/70
-DBP = 70
-MAP = 80
-CCP = 80-10 = 70
cerebral perfusion pressure: autoregulation
-changes in ICP result in compensation
-Increased ICP = Increased BP
-This causes ICP to rise higher and BP to rise.
-Brain injury and death become imminent
cerebral perfusion pressure: expanding mass inside cranial vault
-displaces CSF
-if pressure increases, brain tissue is displaced
ascending reticular activation system
-Tract of neurons in upper brainstem, pons, and midbrain
-Responsible for sleep-wake cycle
-Monitors input stimulation
-Regulates body functions:
-Respiration
-Heart rate
-Peripheral vascular resistance
-Injury may result in prolonged waking state
facial bones
-zygoma- prominent bone of cheek that protects the eyes -> attachment for muscles controlling eye and jaw movement
-maxilla- upper jaw, supports nasal bone, provides lower border of orbit
-mandible- jaw bone
-nasal bones
face
-covered with skin
-flexible and thin
-highly vascular
-minimal layer of subcutaneous tissue
-circulation- external carotid artery -> supplies fafcial area
-branches- facial, temporal, maxillary arteries
buccinator nerve
-buccal branch of buccinator nerve does not innervate muscle -> innervates cutaneous sensation to zygomatic area and sensory of vestibule of oral cavity
-buccal branch of facial nerve innervates buccinator muscles -> facial nerve does facial expression
nasal cavity
-Upper Border: Bones- Junction of ethmoid, nasal, and maxillary bones
-Bony Septum- Right and left chamber
-Turbinates- Vascular mucosa support -> Warm, humidify, and filter incoming air
-Lower Border:
-Bony hard palate
-Soft palate- Moves upward during swallowing
-Nasal Cartilage- Forms nares
oral cavity
-Formed Structures
-Maxillary bone
-Palate
-Upper teeth meeting the mandible and lower teeth
-Floor:
-Tongue
-Connects to hyoid bone- Free-floating U-shaped bone inferior and posterior to the mandible
-Mandible- Articulates with the TMJ joint
salivary glands
-first stage in digestion
-location:
-anterior and inferior to ear
-under tongue
-inside inferior mandible
tonsils
-posterior wall of pharnyx
sinuses
-hollow spaces in cranium and facial bones
-function:
-Lighten head
-Protect eyes and nasal cavity
-Produce resonant tones of voice
-Strengthen area against trauma