Anatomy and physiology of cerebrospinal fluid

Abstract

The cerebrospinal fluid (CSF) is contained in the brain ventricles and the cranial and spinal subarachnoid spaces. The mean CSF volume is 150 ml, with 25 ml in the ventricles and 125 ml in subarachnoid spaces. CSF is predominantly, but not exclusively, secreted by the choroid plexuses. Brain interstitial fluid, ependyma and capillaries may also play a poorly defined role in CSF secretion. CSF circulation from sites of secretion to sites of absorption largely depends on the arterial pulse wave. Additional factors such as respiratory waves, the subject's posture, jugular venous pressure and physical effort also modulate CSF flow dynamics and pressure. Cranial and spinal arachnoid villi have been considered for a long time to be the predominant sites of CSF absorption into the venous outflow system. Experimental data suggest that cranial and spinal nerve sheaths, the cribriform plate and the adventitia of cerebral arteries constitute substantial pathways of CSF drainage into the lymphatic outflow system. CSF is renewed about four times every 24 hours. Reduction of the CSF turnover rate during ageing leads to accumulation of catabolites in the brain and CSF that are also observed in certain neurodegenerative diseases. The CSF space is a dynamic pressure system. CSF pressure determines intracranial pressure with physiological values ranging between 3 and 4 mmHg before the age of one year, and between 10 and 15 mmHg in adults. Apart from its function of hydromechanical protection of the central nervous system, CSF also plays a prominent role in brain development and regulation of brain interstitial fluid homeostasis, which influences neuronal functioning.

Exserohilum Infections Associated with Contaminated Steroid Injections

“…Animal studies have shown a direct communication between the adventitia of cerebral arteries and surrounding CSF. 32 If such a communication exists in humans, it could facilitate fungal angioinvasion in the major CNS arteries. The organism's metabolic requirements for oxygen and iron concentrated in arterial erythrocytes may be an impetus, and protease digestion or physical disruption of the vessel wall may provide the means, for angioinvasion, as described for other fungi.…”

“…Although the dura is typically regarded as impervious and contiguous with the epineurium of spinal nerves, there is evidence that normal CSF resorption involves some flow across the dura and cranial and spinal nerve sheaths, with uptake by lymphatics. 32,39,40 This implies some degree of dural permeability, which may be another potential means of initial fungal entry into the CSF.…”

Diagnosis and Differential Diagnosis of Hydrocephalus in Adults

“…There are also the unpaired third and fourth ventricles. The CSF volume is about 150 ml, and approximately 450 ml are produced each day, which means that the CSF is replaced three times a day [5]. In the classic CSF circulation model, known as the "bulk flow model" [6], the CSF is produced by the choroid plexus which is located primarily in the lateral ventricles and to a lesser extent also in the third ventricle and on the roof of the fourth ventricle.…”

External ventricular drainage-related ventriculitis

“…Así también, la presencia de comorbilidades en este grupo de estudio no demostró significancia estadística (p 0,5). (12,19,(21)(22)(23)(24) Los hallazgos microbiológicos de este estudio coinciden con el de la literatura . Se encontró un porcentaje similar entre cocos Gram positivos y bacilos Gram negativos, siendo S. aureus, S. epidermidis, A. baumanii, y K. pneumoniae los gérmenes más frecuentemente aislados.…”