Dural sinuses/Meninges/Vasculature Flashcards
What layers make up the dura mater?
Periosteal layer and the meningeal layer
This layer is more superficial and attaches to the periosteum of the cranial bones
Periosteal layer of the dura mater
This layer is the deeper layer and is normally fused to the superficial layer of the dura mater
Meningeal layer of the dura mater
What is created when the periosteal layer and the meningeal layer are not fused?
Large, blood-filled sacs == DURAL VENOUS SINUSES
What is immediately deep to the dura mater?
Arachnoid mater
What is the arachnoid trabeculae?
Web of collagen and elastic fibers
What is between the dura and arachnoid mater?
Subdural space
What is between the arachnoid mater and pia mater?
Subarachnoid space
This mater is a layer of connective tissue that tightly adheres to the brain and follows every contour of the brain – innermost cranial meninge
Pia mater
What are the cranial meninges?
Dura mater, Arachnoid mater, Pia mater
What creates the cranial dura septa?
The meningeal layer of dura mater extends deep into the cranial cavity
What are the 4 cranial dura septa?
Falx cerebri, falx cerebelli, tentorium cerebelli, diaphragma sellae
What is the purpose of the cranial dura septa?
To separate specific parts of the brain and provide additional stabilization to the brain
What dural venous sinuses are located in the cranial dura septa?
Superior and inferior sagittal, straight, sigmoid, transverse sinuses
What is housed in the cavernous sinus?
Internal carotid artery and CN VI
What other structures are associated with the cavernous sinus?
CN III, CN IV, CNV1,2, CN VI
What can a cavernous sinus cause?
CN VI palsy – cannot ABduct eye
Describe the arterial supply to the meninges
The external carotid gives off the middle meningeal artery that then splits into the parietal (posterior) and the frontal (anterior) branches to supply all meninges
What nerves innervate the meninges?
Opthalmic, maxillary, mandibular, C2 and C3 spinal nerves
What are the functions of cerebrospinal fluid?
Bathes CNS strucutres, buoyancy, protection and environmental stability
Hydrocephalus
Results from an obstruction in cerebrospinal fluid flow that restricts its reabsorption in the venous bloodstream via the arachnoid granulations
Compared to blood plasma, describe the contents of CSF
Increased Na, H, Ca and decreased K
Where is the carotid sinus?
Superior to the bifurcation (split) of the common carotid, on the internal carotid A.
What is the purpose of the carotid sinus?
It uses baroreceptors innervated by CN IX, to control ANS in response to blood pressure
How many branches does the external carotid A. have?
8
What are the external carotid arterial branches?
Superior thyroid Ascending pharyngeal Lingual Facial Occipital Posterior Auricular Maxillary Superficial temporal
What are the branches of the facial artery?
Cervical: Ascending palatine, tonsilar, submental, glandular
Facial: inferior labial, superior labial, lateral nasal, angular
What are the 3 sections of the maxillary artery?
Mandibular, pterygoid, pterygopalatine
What are the arterial branches off of the mandibular section of the maxillary artery?
Deep auricular, anterior tympanic, inferior alveolar (mental and mylohyoid), middle meningeal, accessory meningeal
What are the arterial branches off of the pterygoid section of the maxillary artery?
Deep temporal, pterygoid branches, massateric, buccal
What are the arterial branches off of the pterygopalaine section of the maxillary artery?
Posterior superior alveolar, descending palatine (greater and lesser), infraorbital, pharyngeal, artery of pterygoid canal, sphenopalatine
Does the internal carotid have branches in the neck?
NO
What are the 3 branches of the internal carotid artery?
Opthalmic, anterior cerebral and middle cerebral
Describe the vertebral artery pathway
Vertebral arteries combine to form basilar
– anterior spinal, posterior inferior cerebellar, anterior inferior cerebellar, pontines, superior cerebella
They then split to form posterior cerebrals that give off a posterior communicating branch
Decreased posterior circulation due to intermittent vertebral artery occlusion – during head extension and rotation due to atherosclerosis
Vertebrobasilar insuffiency
What are some symptoms of vertebrobasilar insufficiency
Dizzy, double vision, numbness/weakness/loss of coordination, slurred speech, nausea
What are some risk factors for vertebrobasilar insuffiency?
Smoking, obese, hypertension/hyperlipidemia, age > 50
What is involved in the circle of willis?
Posterior communicating branch from the posterior cerebals, internal carotid, middle cerebral, anterior cerebrals joined via anterior communicating branch
Proximal stenosis or occlusion of subclavian artery, which causes reverse blood flow through one side of the vertebral artery to supply UE
Subclavian steel syndrome
Symptoms of subclavian steel syndrome?
syncope, different BPs in UE’s, memory problems
