Bacterial Meningitis Pathophysiology. Bacterial meningitis is initially an acute purulent infection of the meninges and subarachnoid space that is followed by an inflammatory reaction in the subarachnoid space, the brain parenchyma, and the cerebral arteries (arteritis) and veins (dural sinus…
Multiple Sclerosis: Overview In temperate climates, multiple sclerosis (MS) is the most common episodic neurologic illness of early adult years. The process begins as periodic and focal loss of central nervous system (CNS) myelin and the oligodendrocytes (OGCs) that synthesize…
Overview and Approach to Stroke Patient Arterial Supply to the Brain and Meninges Overview and Cervical Segments The brain and meninges are supplied by branches that originate from the aorta. The brachiocephalic trunk (or innominate artery ) divides behind the…
Cerebellum and the Fourth Ventricle The fourth ventricle lies posterior to the pons and upper half of the medulla oblongata and anterior to the cerebellum (see Plate 8-1 ). Its upper and lower ends become continuous, respectively, with the cerebral…
Anatomy of the Basal Ganglia and Related Structures Overview of Movement Disorders For the past 30 years, movement disorders have encompassed the study of a group of conditions characterized by poverty of movement, the akinetic-rigid syndromes, and those with excessive…
Coma The term consciousness refers to a state of awareness of self and one's environment. Assessing consciousness in another person relies on judging that individual's performance or behavior in some mental function and arousal or response of awakening to a…
Anatomic Relationships of the Hypothalamus The hypothalamus is a small area, weighing about 4 g of the total 1,400 g of adult brain weight, but it is the only 4 g of brain without which life itself is impossible. The hypothalamus is so…
Limbic System The limbic system is the only brain area receiving major hypothalamic input and providing interconnection with widespread cortical areas. Major limbic structures include the amygdala, piriform cortex (parahippocampal gyrus, uncus + amygdala) , hippocampus, substantia innominata, and septal…
Surfaces of Cerebrum The cerebrum is divided into right and left hemispheres by a longitudinal fissure. Each hemisphere has three surfaces—superolateral, medial, and inferior—all of which have irregular fissures, or sulci, demarcating convolutions, or gyri. Although there are variations in…
Initial Specification of the Nervous System: The Embryo at 18 Days After fertilization and implantation, the embryo consists of a single cell layer called the inner cell mass. The inner cell mass sits at the bottom of a fluid-filled cavity…