Clinical Module Summary Notes - Central Nervous System

Clinical Module Summary Notes - Central Nervous System -...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Clinical Module 2 Imaging of the Central Nervous System Anatomy Arterial blood derived from the internal carotid arteries (these bifurcate at the angle of the mandible arising from the common carotid arteries, each of which also produces an external carotid branch that courses upwards over the face); and the basilar artery (produced when the two vertebral arteries join together at the level of the foramen magnum of the occipital bone --thereafter, the basilar divides to form the two posterior cerebral arteries). The two arterial supplies are inter-joined at the arterial circle (circle of Willis), thereby allowing some collateral blood flow in the event that one or more portions of the circle are occluded (past this point -- above the Circle of Willis -- the arteries can be thought of as being terminal vascular branches as no collateralization is possible). The cerebra are perfused with arterial blood delivered by branches of three major pairs of arteries -- the anterior, the middle and the posterior cerebral arteries (each occurs as a left and a right artery). Regional blood flow is very specifically supplied to circumscribed portions of the cerebra (these regions are called watersheds ), each being nourished by particular arteries and their branches (a clear understanding of the specific volumes perfused by each of the watersheds is important in interpreting flow and static study appearances). The cerebellum gets its arterial blood from branches coming off the basilar artery. Venous drainage occurs through a system of venous sinuses (these are different from veins in that they lack valves or the ability to expand or contract). In the mid-sagittal plane there is the superior sagittal sinus (this runs from the Crista Galli of the frontal bone back to the Tentorium, and is contained within the falx cerebri). At the base of the falx, just above the corpus callosum is a smaller sinus paralleling the course of the superior sagittal sinus -- this is the inferior sagittal sinus. These two sinuses are joined at their posterior limits by a straight, tunnel-like sinus called the straight sinus (some individuals have a tail-like extension of this passing down into the region beneath the tentorium (this is known as the occipital sinus). 1 posterior cerebral artery basilar artery with branches to cerebella vertebrals passing through transverse foramina
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Sandwiched within the two membranes which compose the tentorium cerebelli (the “Saran Wrap-like” sheet which lies between the cerebra and the cerebella) are the left and right transverse sinuses. These sinuses lie perpendicular to the plane of the sagittal sinuses, and near their lateral ends they abruptly bend downwards to form the sigmoid sinuses which penetrate the inner surface of the occipital bone emerging on the exterior surface of the skull as the internal jugular veins. Cerebrospinal fluid
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/20/2008 for the course NUCLEAR ME 4203 taught by Professor Heggie during the Spring '08 term at Missouri (Mizzou).

Page1 / 17

Clinical Module Summary Notes - Central Nervous System -...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online