L6 blood supply to the CNS Flashcards
(recap) Through what **artery branch **does the subclavian artery supply the CNS?
- vertebral artery
what are the** 2 systems of blood supply **to the brain?
1.** Carotid -** internal carotid artery & its branches (anterior circulation)
2. Vertebrobasilar - vertibral and basilar branches (posterior circulation)
what do the internal carotid arteries and their branches supply?
- they supply blood to the majority of the forebrain
- this is why they are classified as the** anterior circulation**
where do the vertebral arteries supply blood to?
- supply blood to the spinal chord
- brainstem
- cerebellum
- posterior cerebral hemispheres (ie occipital and temporal lobes)
what is the circle of willis?
- an anatomical structure that provides an anastomotic **connection between the anterior and posterior circulations **
- a circle around the hypothalamus and optic nerve at the base of the brain
Briefly describe the anterior circulation
ie describe the branches of the ICA
Internal carotid artery branches
* **middle and anterior cerebral artery **- supply the cortex and penetrate the brain to supply deep structures
* ophthalamic artery
* anterior choroidal artery
* posterior communicating artery
Briefly describe posterior circulation
ie the branches of the vertebasilar system
vertebrobasilar artery and branches
* vertebral artery
* posterior inferior cerebellar artery (PICA)
* anterior inferior cerebellar artery (AICA)
* Basilar artery
* pontine branches
* superior cerebellar artery
* posterior cerebellar artery
what are the 3 arteries that run along the spinal chord? (longitudinal vessels)
- anterior spinal artery
- right posterior spinal artery
- left posterior spinal artery
what are the arteries that supply **each segment **of the spinal cord called?
segmental arteries
what do the segmental vessels split into?
the anterior and posterior **radicular branches **
what are the** roles/ function** of the anterior and posterior radicular branches?
- they run into cord along dorsal and ventral nerve roots
- supply lumbar & sacral regions of spinal cord
what are the 2 types of cerebral veins?
- superficial
- deep
what is the function of the superficial cerebral vein?
- drains cortex
- empties blood into adjacent sinuses of dura
what is the function of the deep cerebral veins?
- they drain the deeper structures - the basal nuclei, internal capsule (white matter structure in brain) & choroid plexus
what are the dural venous sinuses?
- they are major vascular channels contained between the meningeal & periosteal layers of the dura mater
where are most of the dural venous sinuses located next to?
the falx cerebri (fold in dura mater) & tentorium cerebelli (extension of dura mater)
what are the major dural venous sinuses?
- superior saggital sinus
- inferior saggital sinus
- straight sinus
- transverse sinus
- sigmoid sinus
what is the main function of the dural venous sinuses?
- to drain all venous blood within the cranial cavity into the internal jugular vein
- they also drain CSF through arachnoid granulations
Describe the superior saggital sinus
- **occupies **the longitudinal fissure of the brain (line through both hemipsheres)
- lies along the superior margin of the falx cerebri
Describe the inferior saggital sinus
- lies along inferior margin of falx cerebri
- joins the great cerebral vein
Describe the** straight sinus**
- midline structure
- located at the** posterior end of the falx cerebri** and the middle of the tentorium cerebelli
what is the confluence of sinuses?
- the point of union between the superior saggital sinus, straight sinus, occipital sinus and transverse sinuses
describe the transverse sinus
- **begins **at the confluence of sinuses
- extends along the edges of the tentorium cerebelli
- **paired **sinus - right and left
Describe the sigmoid sinus
- **continuation **of straight sinus
- paired sinus
- S shaped sinuses
- joins the internal jugular vein
