INtercranial region Flashcards
What are the layers of the scalp?
Skin
Conective tissue
Aponeurosis of occiptofrontalis muscle
Loose areolar tissue
Perineum
Where in the scalp would a wound gap and where wouldn’t it?
Gap: Aponeurosis
Doesn’t gap: Connecive tissue
what is the dangerous area of the scalp ?
Loose areolar tissue due to prescence of emissary veins
What is black eye ?
collections of fluid, pus and blood spreading to the eyelid
Where can de scalping occur?
Loose areolar tissue
What are diploic veins?
The diplioc veins are large tin walled valves, that channel in the diploe between the inner and outer layers of the corticol bone in the skull.
what happens to the diploe in sickle cell anaemia?
It increases in thicnkess due to hyperplasia
what are the layers of the dura inside tout ?
PAD
PIa
Arachnoid
Dura
What are the dural folds?
Falx cerebri
Tentorium cerebelli
Falx cerebelli
Diaphragma sellae
What are the borders of the falx cerebri?
upper border: superior saggital sinus
lower free border: inferior saggittal sinus
Base: straight sinus
what is the falx cereblli?
small cresecent shaped projects vertically downward in posterior cranial fossa between the two cerebellar hemisphere.
What is the tentorium cerebelli?
A horizontal roof between cerebelar and cerebellar hemisphere.
What are the layers of the dura?
meningeal and periostal
what is the diaphragma sellae?
small dural fold extending between he 4 clinoid processes roofing the hpophyseal fossa and has a central opening passage of pitutary gland.
What is the blood suply of the dura mater?
Occipital v. and vertebral v.
middle meningeal, opthalamic meningeal, accessory meningeal
What is the origin of the middle meningeal artery?
The first part of the maxillary artery
What is the course of the MMA?
Runs upwards to enter the middle cranial fossa through the foramen spinosum
Where is the center of the pterion located?
4cm above the middle of zygomatic arch and 3 1/2 cm behind the frontozygomatic suture is grooved on the inside by the middle meningeal vs. its teh thinnest part of the skull and liable to fracture
What is an epidural hematoma?
MMA rupture usually due to a blow to the pterion
What are the dural venous sinuses?
Venous channels lying between the 2 dural layers
How can rhinorrhea occur?
Head trauma affecting the cribriform plate of the ethmoid bone causing a leak of CSF from the anterior cranial fossa to the nasal cavity
What is otoorrhea?
Head trauma that affects the pterous temporal bone will cause leak of csf from middle cranial fossa into the middle ear then through the external auditory meatus
What is the site of the superior saggital sinus?
Along the upper attached margin of falx cerbri
What is the course of the suprior saggital sinus?
Starts anteriorly and runs upwards and backwards
Ends opposie internal occipital protuberance by turning usually to the right side to continue as the right transverse sinus
What is the dilated posterior end of the superior sagittal sinus referred to as?
Confluence of sinuses
What is the cavernous sinus ?
A large venous space lying the middle cranial fossa on either side of body of sphenoid bone
What is the extent of cavernous sinus?
Its anterior end reaches the medial end of superior orbital fissure to its posterior end that reaches the apex of petrous temporal branch
What are the structures in the lateral wll of sinus from above to downwards?
oculomotor nerve
Trochlear nerve
Opthalmic nerve
Maxillary nerve
What structures pass through the sinus?
internal carotid artery and abducent nerve
What is the cavernous sinus communicate with ?
Pterygoid venous plexus via emissary vs.
Facial v. via superior opthalmic v.
Its fellow on the opposite side via 3 intercavernous sinuses
Which cranial nerves are affected by thrombosis of cavernous sinus?
cRanial nerve III, IV & VI
What are the clinical syptoms of thrombsis of cavernous sinus?
HIgh fever
Periorbital edema and chemosis (conjunctival edema)
Cranial nerve palsises (most common in cN VI)
Decreased visual acuity
What are emissary veins?
Valveless veins connecting dural sinuses and extracranial veins
