Sectional AnatomyWeek 3:

The Brain

Bellingham Technical CollegeBiology 130

Instructor: Ken WilkersonE-mail: wilkersk@hotmail.com

Labeling Exercises

• Use your pgdn key to scroll through the following scans and try to name the labeled anatomy before revealing the answers.

A

B

C

D

Clivus

Medulla Oblongata

4th Ventricle

Cerebellum

MRI WO Contrast T2 Weight

A

B

C

D

Middle Cerebral Artery

Posterior Cerebra Artery

Mid-Brain

Vermis of Cerebellum

MRI WO Contrast T2 Weight

A

B

C

D

Ant. Horn of lateral ventricle

Head of caudate nucleus

Thalamus

Post. Horn of lateral Ventricle

CT Brain WO contrast

Carotid ArteryA.

B. Jugular Vein

C. Vertebral Arteries

CTA Brain

CTA Brain Maximum Intensity Projection

A.

B.

C.

Anterior Cerebral Artery

Middle Cerebral Artery

Post. Cerebral Artery

Intracranial Hemorrhage

• As an imaging technologist in advanced imaging modalities, it is important to understand the differences, and recognize the physical appearance of different classifications of intracranial hemorrhage.

• The following slides will help you recognize and identify different types of intracranial hemorrhage.

Types of Intracranial Hemorrhage

Intra-axial• intraparenchymal

– Bleeding within the brain tissue.

• Intraventricular– Bleeding into the ventricles

Extra-axial• Epidural

– Bleeding that occurs between the dura and cranial bone.

• Subdural– Subdural hematoma occurs when

there is tearing of the bridging vein between the cerebral cortex and a draining venous sinus. At times they may be caused by arterial lacerations on the brain surface.

• Subarachnoid– meningeal layers.occuring between

the arachnoid and pia

Intra-axial

• intraparenchymal

– Nontraumatic intraparenchymal hemorrhage most commonly results from hypertensive damage to blood vessel walls e.g.: - hypertension -eclampsia - drug abuse, but it also may be due to autoregulatory dysfunction with excessive cerebral blood flow e.g.: - reperfusion injury - hemorrhagic transformation - cold exposure - rupture of an aneurysm or arteriovenous malformation (AVM) - arteriopathy (e.g. cerebral amyloid angiopathy, moyamoya) - altered hemostasis (e.g. thrombolysis, anticoagulation, bleeding diathesis) - hemorrhagic necrosis (e.g.tumor, infection) - venous outflow obstruction (e.g. cerebral venous sinus thrombosis). Nonpenetrating and penetrating cranial trauma can be also common causes of intracerebral hemorrhage.

• Intraventricular– Intraventricular hemorrhage has been

found to occur in 35% of moderate to severe traumatic brain injuries.[11] The injury requires a great deal of force to cause. Thus the hemorrhage usually does not occur without extensive associated damage, and so the outcome is rarely good.[12][13]

– Prognosis is also dismal when IVH results from intracerebral hemorrhage related to high blood pressure and is even worse when hydrocephalus follows.[1] It can result in dangerous increases in intracranial pressure and can cause potentially fatal brain herniation.[1]

Extra-Axial

• Epidural Hematoma– Bleeding between the dura of the brain and the

inner surface of the cranium.• This is a traumatic injury caused by a sharp blow to the

head. Often this type of hemorrhage will be associated with an underlying cranial fracture.

Extra-Axial

• Subdural Hematoma

• Subdural hematomas are usually the result of a serious head injury. When one occurs in this way, it is called an "acute" subdural hematoma. Acute subdural hematomas are among the deadliest of all head injuries. The bleeding fills the brain area very rapidly, compressing brain tissue. This often results in brain injury and may lead to death.

• Subdural hematomas can also occur after a very minor head injury, especially in the elderly. These may go unnoticed for many days to weeks, and are called "chronic" subdural hematomas. With any subdural hematoma, tiny veins between the surface of the brain and its outer covering (the dura) stretch and tear, allowing blood to collect. In the elderly, the veins are often already stretched because of brain atrophy (shrinkage) and are more easily injured.

Intraparenchymal Hemorrhage

Intraventricular Hemorrhage

Epidural Hemorrhage

Note convex appearance of hemorrhageThis is caused by the pressure of the bloodPushing against the dural membrane

Subdural Hemorrhage

Concave, “quarter moon” appearance suggesting separation of the surface of the brain from the dura.. Also, note the appearance of blood in the sagittal sinus.

Subarachnoid Hemorrhage

The presence of blood within the Sylvian (lateral) fissures is a clear indication of SAH.

Last Slide

Keep up the good work!

All material in this presentation is testable.