Lamictal

By R. Ali. State University of New York College at Purchase.

CSF produced in CLINICAL ASPECT the lateral ventricles flows via the foramen of Monro (from The CSF flows down around the spinal cord and into the each lateral ventricle) into the third ventricle discount lamictal 25 mg, and then lumbar cistern. Sampling of CSF for clinical disease, through the aqueduct of the midbrain into the fourth ven- including inflammation of the meninges (meningitis), is tricle. CSF leaves the ventricular system from the fourth performed in the lumbar cistern (see Figure 1, Figure 2C, ventricle, as indicated schematically in the diagram. The CSF is then analyzed, for cells, pro- intact brain, this occurs via the medially placed foramen teins, and other constituents to assist or confirm a diag- of Magendie and the two laterally placed foramina of nosis. Luschka (as described in the previous illustrations) and The major arteries of the circle of Willis travel through enters the enlargement of the subarchnoid space under the the subarachnoid space (see Figure 58). An aneurysm of cerebellum, the cerebello-medullary cistern, the cisterna these arteries that “bursts” (discussed with Figure 59A) magna. The cisterna magna is found inside the skull, just will do so within the CSF space; this is called a subarach- above the foramen magnum (see Figure 18). CSF flows through the subarachnoid space, between Hydrocephalus has been discussed with the previous the pia and arachnoid. The caudate nucleus organization follows the curvature of the lateral ventricle into the temporal lobe (see Figure OL BASAL GANGLIA: ORIENTATION and Figure 25). There are large collections of gray matter within the hemi- These basal ganglia are involved in the control of spheres, belonging to the forebrain, in addition to the complex patterns of motor activity, such as skilled move- white matter and the ventricles already described. There are two aspects to this involve- neuronal groups are collectively called the basal ganglia. Oftentimes the term striatum is used for the basal ganglia, The second concerns the quality of the performance of the but this term is not always used with neuroanatomical motor task. It seems that different parts of the basal ganglia precision. Our understanding of the functional role of the are concerned with how rapidly a movement is to be basal ganglia is derived largely from disease states affect- performed and the magnitude of the movement.

The pars reticulata lies adjacent to the tain visual movements (see Figure 41B) cheap lamictal 25 mg fast delivery. These nuclei give cerebral peduncle and contains some widely dispersed rise to a fiber tract, the tecto-spinal tract, a descending neurons; these neurons connect the basal ganglia to the pathway that is involved in the control of eye and neck thalamus as one of the output nuclei of the basal ganglia movements; it descends to the cervical spinal cord as part (similar to the globus pallidus internal segment, see Figure of the medial longitudinal fasciculus (MLF) (see Figure 53). The pars compacta is a cell-rich region, located more 51B). The MLF stains heavily with a myelin-type stain and These are the dopaminergic neurons that project to the is found anterior to the cranial nerve motor nucleus, next neostriatum (discussed with Figure 52). Loss of these to the midline, at this level as well as other levels of the neurons results in the clinical entity Parkinson’s disease brainstem. Also to be noted at this level is the brachium (discussed with Figure 52). With a section that has been stained for myelin, the nucleus is CLINICAL ASPECT seen as a clear zone. The red nucleus gives origin to a A specific lesion involving a thrombosis of the basilar descending pathway, the rubro-spinal tract, which is artery may destroy much of the brainstem yet leave the involved in motor control (see Figure 47 and Figure 48). Few people actually The oculomotor nucleus (CN III) is quite large and survive this cerebrovascular damage, but those that do are occupies the region in front of the periaqueductal gray, left in a suspended (rather tragic) state of living, known near the midline; this identifies the level as upper midbrain by the name “locked-in” syndrome. These motor neurons are large consciousness, with intellectual functions generally intact, in size and easily recognizable. The parasympathetic por- meaning that they can think and feel as before. However, tion of this nucleus is incorporated within it and is known usually, all voluntary movements are gone, except perhaps as the Edinger-Westphal (EW) nucleus (see Figure 8A). This means that they portion of the red nucleus and exit between the cerebral require a respirator to breathe and 24-hour total care.