Cranial Cavity, Meninges, and Dural Sinuses Flashcards
90% of brain size is reached by what age?
5 years old
What is Pterion?
a cranial metric point used for clinical orientation
* frontal, spheoid, temporal and parietal bones all meet
What bone structure houses the pituitary gland?
hypophyseal fossa
What is the name of the epicranial aponeurosis? What does it connect?
gala aponeurotica
*connects the frontalis muscle and occipitalis muscle
frontalis muscle vs occipitalis muscle insertion points?
Why are these points important?
- frontalis muscle: inserts superficially IN SKIN
- occipitalis muscle: inserts into bone
- *important for location of bleeds and infection; since fontalis inserts in skin it allows blood to flow towards face (occipitalis doesn’t bc bone connection stops it)
What does S.C.A.L.P. stand for?
- Skin= Contains hair follicles, sweat and sebaceous glands
- Connective (subcutaneous) tissue= Thick, dense, richly vascularized and innervated subcutaneous layer
- Aponeurosis= Strong, tendinous sheath which serves as attachment for muscles
- Loose areolar tissue= Sponge-like layer that allows free movement of the 1st three layers
- Pericranium= Dense layer that forms the external layer of the neurocranium
What part of S.C.A.L.P. makes the scalp proper? is in contact with bone?
- S.C.A. = scalp proper
* Pericranium in contact with cranium bone
Where is BS to scalp located in what layer? comes from?
BS to the scalp is from both internal and external carotid’s (with external being all superficial structures)
**Blood runs in 2nd layer above gala aponeurotica!
Why does the scalp bleed so much?
Arterial walls are firmly attached to the connective tissue in which they are embedded. Therefore, they have a limited ability to constrict if cut and will bleed profusely.
Why do deep scalp wounds will gape widely when the epicranial aponeurosis is lacerated in the coronal plane?
because of the pull of the frontal and occipital bellies of the occipitofrontalis muscle
Scalp bleeding/Infections CAN and canNOT spread where?
- *CAN spread to the eyes and nose bc the frontalis muscle inserts into the skin/subcutaneous tissue
- *canNOT spread to neck bc the occipital belly of the occipitofrontalis muscle inserts directly to bone
- *canNOT spread laterally bc the epicrania aponeurosis is continuous with the temporal fascia that attaches to the zygomatic arches
Any kind of blood or infection will spread what direction in scalp?
anteriorly
*NOT laterally or posteriorly
What is the FIRST line of defense for head? But what is the MAJOR defense?
skin is first line of defense
*But the bone is the real deal
what does diploe mean?
diploic means two layers of compact bone separated by spongy
*ALL flat bones
Emissary Vein vs Diploic veins
- Diploic veins - running within the spongy bone
- Emissary veins - draining from the scalp inwards