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82 Cards in this Set
- Front
- Back
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5 Scalp layers:
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Skin
Connective Tissue Aponeurosis Loose areolar tissue Pericranium |
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What is the skin of the scalp like?
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Thin (except in occipit)
Sweat/sebacious glands Hair Good vascular supply/drainage |
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What is the scalp connective tissue like?
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Thick, dense, rich vasculature
Innervated by cutaneous nn. |
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another name for the scalp aponeurosis:
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epicranial apon.
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what is the epicranial aponeurosis?
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Broad/strong tendon sheet covering calvaria; attachment for muscles.
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what muscles are attached to the aponeurosis?
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-Occipitofrontalis
-Temporoparietalis -Superior auricular |
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What is the collective name for the muscles and aponeurosis connecting them?
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Epicranius
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What is the epicranius innervated by?
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The facial nerve - CN VII
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What is the Scalp Proper?
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-Skin
-Connective tissue -Aponeurosis The first three layers |
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What is the function of the Loose areolar layer?
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Allows free movement of the scalp proper over the calvaria
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What is the Loose areolar layer?
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Spongey layer with potential space for infection/injury fluid
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What is the pericranium?
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Dense connective tissue - forms ext. neurocranium periosteum.
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What holds superficial scalp wounds together?
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Aponeurosis
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How do deep and superficial scalp wounds caused by coronal lacerations differ?
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Superfic: don't gape
Deep: gape - b/c the aponeurosis is cut and the occipitofrontalis muscle pulls apart. |
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Which layer of the scalp is the "Danger Area"?
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Layer 4 - Loose Areolar
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Why is the loose areolar layer dangerous?
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Because pus/blood spread easily within it; can spread infection both within, and into cranium via emissary veins.
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What forms when hair follicles get obstructed?
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sebacious cysts
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What is a Cephalhematoma?
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Benign area of blood trapped btwn the pericranium/calvaria in a newborn; caused by traumatic birth.
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What are cranial meninges and where are they?
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Brain coverings immediately internal to the cranium (bone).
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What are the 3 functions of the meninges?
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1. Protection of brain
2. Framework for vasculature 3. Allow for subarachnoid space |
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What are the 3 layers of the meninges?
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1. Dura mater
2. Arachnoid mater 3. Pia mater |
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What is each layer like in general?
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Dura = tough/thick
Arachnoid = thin Pia = delicate |
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What is the relationship between the arachnoid/pia maters?
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-Continuous; together they are the leptomeninx.
-Separated by subarachnoid space |
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What lies within the subarachnoid space?
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CSF!!
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What is the purpose of the subarachnoid space?
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to maintain the balance of CSF in the brain.
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Where is CSF produced?
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From choroid plexuses in the ventricles within the brain.
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What is the dura mater structure like in general?
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Bilayered - aka pachymeninx
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What are the dura mater's 2 layers?
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1. External periosteal layer
2. Internal meningeal layer |
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Where is the external periosteal layer of the dura mater?
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just inside the cranium surface; it is continuous with external periostium at cranial foramina.
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Which dura mater layers are continuous with that of the spinal cord?
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Only the internal meningeal layer.
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What is the internal meningeal layer of the dura like?
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Strong and fibrous; continus w/ spinal dura at foramen magnum.
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Which layer of dura mater forms dural infoldings, and what are the four infolding names?
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-Meningeal layer of dura - forms
1. Falx cerebri 2. Tentorium cerebelli 3. Falx cerebelli 4. Diaphragma sellae |
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What brain compartments are separated by falx cerebri?
In what plane does it lie? |
Lies in vertical longitudinal cerebral fissure; separates R/L cerebral hemispheres.
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What are the cranial attachments of falx cerebri?
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Anterior: Frontal crest
Posterior: Internal occipital protuberance |
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How does the falx cerebri end?
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B/c contin w diphragm sellae
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What brain regions does tentorium cerebelli separate?
In what plane does it lie? |
Lies somewhat horizontally; separates occipital cerebral lobes from the cerebellum.
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What are the cranial attachments of tentorium cerebelli?
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-Front/rostral: clinoid processs
-Side/rostral: Petrous temporal -Side/posterior: occipital and parietal bones. |
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Into what compartments does tentorium cerebelli segment the brain?
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-Supratentorial
-Infratentorial |
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What is the medial/anterior side of tentorium cerebelli like?
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Concave and open - free to provide a gap that lets the brainstem continue into middle cranial fossa.
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What is the gap created by tent. cerebelli called (for continuance of brainstem)?
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Tentorial notch
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What does falx cerebellum separate, and what is its cranial attachment?
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Vertically oriented to separate R/L cerebellar hemispheres; attached to internal occipital crest
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What is diaphragma sellae? What are its attachment points?
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The bedcovers for the pituitary gland; circular sheet of dura; suspends from clinoid processes.
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What is a tentorial herniation?
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Slippage of a tempora lobe through the tentorial notch
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What can cause tentorial herniation? (2 contributors)
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1 Supratentorial brain tumors increase intracranial pressure; 2 Tentorial notch is a little bigger than it needs to be.
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What can result from tentorial herniation?
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-Temporal lobe laceration by the tentorium itself
-Occulomotor lesions from stretching/compression. |
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Pituitary tumors making diaphragma sellae bulge may result in what 2 symptoms?
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1. Hormone disturbances (disturbance of pituitary gland)
2. Visual - from pressure on the optic chiasm. |
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What important circulatory structures lie between the periosteal/meningeal layers of dura mater?
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Dural venous sinuses
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What is the function of the dural venous sinuses?
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To recieve blood from surface veins and the brain in general; return it to IJV.
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What is the highest sinus? Where does it end?
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Superior sagittal sinus; ends at the confluence of sinuses.
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What meets at the confluence of sinuses?
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-Superior sagittal sinus
-Straight sinus -Occipital sinus -Transverse sinuses |
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What are lateral venous lacunae?
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Lateral expansions of the superior sinus
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What are arachnoid granulations?
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Tufts of arachnoid extending into the sinuses - esp lateral venous lacunae.
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What is the purpose of arachnoid granulations?
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To allow transfer of CSF from the arachnoid space to the venous system.
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Where is the inferior sagittal sinus located, & how does it end?
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-Inferior border of falx cerebri
-Ends into straight sinus |
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What 2 structures form the straight sinus?
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-Inferior sagittal
-Great cerebral vein |
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Where does the straight sinus run?
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-From the union point of inf sagittal/great cerebral vein;
-To confluence of sinuses |
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What happens to blood circulation at the confluence of sinuses?
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It is drained into transverse sinuses
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Where does blood flow from the transverse sinuses?
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Into sigmoid sinuses
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Where does blood flow from sigmoid sinuses?
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Into IJV after the sigmoids course through the jugular foramen.
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What does the occipital sinus allow to communicate w/ the sinus system?
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Internal vertebral venous plexuses.
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Where is the cavernous sinous located?
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On either side of sella turcica on the sphenoid bone
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Where does blood flow into the cavernous sinus from?
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-Superior/inferior opthalmic v.
-Superfic. middle cerebral vein -Sphenoparietal sinus |
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What do the cavernous sinuses communicate with?
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Intercavernous sinuses around the pituitary gland stalk.
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Where do the cavernous sinuses drain into?
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Down/backward into superior adn inferior petrosal sinuses.
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Where do the superior petrosal sinuses run?
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From cavernous sinus to transverse sinuses (where they become sigmoid)
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Where do the inferior petrosal sinuses run?
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In a groove between petrous temporal & basilar occiput. Empty into IJV directly.
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Finish up neurovasculature of dura
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ok
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What structures make up the ventricular system of the brain?
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-2 lateral ventricles
-3rd ventricle -4th ventricle -Cerebral aqueduct |
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What fills the ventricules?
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CSF - produced from choroid plexuses.
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How do the lateral ventricles communicate with the 3rd?
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Through interventricular foramen
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What does the 3rd ventricle flow into?
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The cerebral aqueduct
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What does the cerebral aqueduct connect?
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The 4th aqueduct w/ the 3rd.
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What does the 4th ventricle drain into?
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-Spinal cord
-Median aperture -2 Lateral Apertures |
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What do the median/lateral apertures flow into?
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Subarachnoid space
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What is special about these apertures?
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It is the only site where ventricular CSF can get into the subarachnoid space!
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How much CSF is secreted daily?
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400-500 mL
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What secretes CSF?
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Choroid plexuses within the ventricles.
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What happens to CSF after it circulates thru subarachnoid space and into cisterns?
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Absortn via subarachnoid granulations extending into venous system.
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What venous structures recieve CSF from subarachn. granules?
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-Superior sagittal sinus
-Lateral lacunae |
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What cranial site is used for CSF puncture? In whom is this the preferable site?
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Cerebellomedullary cistern - site of choice in infants and young kids.
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What is obstructive hydrocephalus?
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Enlargement of the head due to overproduction of CSF, obstruction of CSF flow, or interference w/ CSF absorption.
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Finish vasculature of brain
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ok
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