New—Lab 5: Blood supply and circulation

Arterial blood supply

Review from FMS 501

Vertebral arteries

Supplying the brainstem and cerebellum

    • Anterior and posterior spinal
    • Posterior inferior cerebellar
    • Basilar (unpaired)—multiple pontine branches also come directly off the basilar artery
      • Anterior inferior cerebellar
      • Superior cerebellar
        • Posterior cerebral posterior communicating
Internal carotid

Supplying the midbrain, thalamus, hypothalamus, and cerebrum

    • Middle cerebral
    • Anterior communicating
    • Anterior cerebral

An episode of vascular insufficiency to neurons leads to a stroke.

Ischemic strokes are sudden blockages of blood flow to parts of the CNS are most commonly caused by a thrombus or an embolus. Clinical presentations of vascular insufficiency often present as specific functional losses.

Figure 5.1.  Anterior and posterior circulation (dashed line indicates the circle of Willis). Blood Supply of the Central Nervous System; Essential Neuroscience, 3e, 2015, Copyright © Wolters Kluwer. Accessed July 16, 2018.
Figure 5.1. Anterior and posterior circulation (dashed line indicates the circle of Willis). Blood Supply of the Central Nervous System; Essential Neuroscience, 3e, 2015, Copyright © Wolters Kluwer. Accessed July 16, 2018.
Figure 5.2. Vascular territories of the cortex. Commons.wikipedia.org.

Figure 5.3. Coronal section of cerebral artery supply. 


    • ACha=Anterior choroidal
    • BA=Basilar
    • AICA=Anterior inferior cerebellar (other abbreviations previously mentioned).

From Neuroanatomy: A Laboratory Guide (2e); Jansen and Lampa.

Figure 5.4. Lateral and medial views of functional areas of the cortex. From Neuroanatomy: A Laboratory Guide (2e); Jansen and Lampa.
Figure 5.5. Peer teaching exercise: For each of the arteries listed here, one student will take 5 minutes to first demonstrate on a brain specimen or using images to describe the area that was previously introduced during Lab 1, supplied by each assigned artery. Then relate this area to the predictive signs from focal ischemia, a stroke, or TIA, and entertain questions from the fellow group members.

Table 1. Anterior arterial circulation territories.

Anterior circulation

Territory

Ischemic loss of function

Internal carotid/central artery of retina

Retina

 

 

Monocular blindness

 

Middle cerebral artery

Lateral motor area (precentral gyrus): Upper division

Contralateral face and arm weakness

 

Lateral sensory area (postcentral gyrus): Upper division

Contralateral face and arm anesthesia

 

Internal capsule (lateral striate artery)

Contralateral arm, face, leg weakness and anesthesia

 

Inferior frontal gyrus: Lower division

Motor (Broca’s) aphasia

 

Frontal eye fields

Gaze to affected side

 

Superior temporal gyrus: Lower division

Receptive (Wernicke’s) aphasia

 

Angular gyrus

Hemianopia (either), alexia (left)

 

Inferior parietal lobule (non-dominant side)

Contralateral sensory neglect, dressing apraxia, constructional apraxia

 

Entire territory of middle cerebral artery (proximal to bifurcation into superior and inferior divisions)

Contralateral hemiparesis and hemianesthesia, plus global aphasia if dominant hemisphere affected

Anterior cerebral artery

Medial motor and sensory area (paracentral lobule)

Contralateral leg weakness and anesthesia

 

Prefrontal cortex (orbital gyri and anterior pole of frontal lobe)

Apathy w/ potential memory loss

Table 2. Posterior arterial circulation territories

Posterior circulation

Territory

Ischemic loss of function

Posterior cerebral artery

Occipital lobe

Homonymous hemianopia (with macular sparing), alexia without agraphia

 

Thalamus (diencephalon)

Hemi-sensory loss

 

Midbrain

Oculomotor nerve palsy (mydriasis, diplopia), contralateral hemiparesis, hemi-sensory loss, possible loss of consciousness

Basilar artery*

Basal pons

Contralateral hemiparesis, CN VI signs

 

Anterior midbrain

Limb ataxia, medial rectus palsy/fixed and dilated pupil

Superior cerebellar artery**

Lateral rostral pons

Optokinetic nystagmus, contralateral sensory loss (vibration, touch, position and pain and temperature)

Anterior inferior cerebellar artery**

Lateral caudal pons

Ipsilateral facial paralysis, gaze palsy, deafness and tinnitus

 

Vermis, anterior lobe of cerebellum

Ipsilateral limb ataxia, nystagmus, vertigo, nausea

Posterior inferior cerebellar artery**

Lateral medulla

Vertigo, loss of pain and temperature from the limbs and trunk on contralateral side, loss of pain and temperature over the face on the ipsilateral side, truncal ataxia, dysphagia/dysphonia/palatal paralysis, Horner Syndrome

 

Inferior cerebellar peduncle

Ataxia (limb and truncal)

Vertebral artery*

Medial medulla, anterior spinal cord

Contralateral hemiparesis; touch, vibration and positional sense loss; CN XII sign

Note: Many cerebellar signs are very similar if superior cerebellar, anterior inferior cerebellar, and posterior inferior cerebellar arteries are occluded.

*Paramedian branches of the vertebral-basilar (both short and long)

**Circumferential branches of the vertebral-basilar (long)

Venous circulation

  • The veins of the cerebrum drain into dural venous sinuses, which mostly drain into the internal jugular vein.
    • Cerebral veins
      • Great cerebral vein (of Galen): Deep venous drainage
        • Formed by internal cerebral veins which drain the diencephalon and basal ganglia
      • Superior cerebral veins (numerous): Superficial venous drainage drains into the superior sagittal sinus
  • Figure 5.6. Venous sinus schematic. Figure from Neuroanatomy: A Laboratory Guide (2e); Jansen and Lampa (2018).
    Review of dural venous sinuses (see Figure 5.6 and Figure 5.7); review FMS 501 notes
    • Superior sagittal sinus (located superior marginal of falx cerebri)
      • Superior cerebral veins drain into the superior sagittal sinus
      • Contains arachnoid villi where the CSF is re-enters the venous system
    • Straight sinus: Ends posteriorly in confluence of sinuses; receives blood from the great cerebral vein (of Galen) and inferior sagittal sinus
    • Confluence of sinuses
    • Transverse sinuses
    • Sigmoid sinuses
    • Jugular bulb (of internal jugular vein)
Figure 5.7. MR venogram of major venous sinuses. Figure from Clinically Oriented Anatomy, 8e, 2018. Accessed August 6, 2018.

Clinical significance of the dural venous sinuses

Besides returning blood from the nervous tissue of the cranial central nervous system, they are also potential routes for infections from more superficial vessels, as well as possible locations of venous thrombi. Signs from increased ICP result from occlusion of the dural sinuses.

Table of Contents
Headshot of Steve Lampa, PhD · Clinical Associate Professor
Steve Lampa
PhD · Clinical Associate Professor
envelope icon