Essay On Subarachnoid Space
The brain and the spinal cord of the central nervous system are buffered by a number of protective layers known as the meninges. These include three main membranes of connective tissue including: the dura mater, the arachnoid layer and the pia mater [6]. The two innermost layers, collectively known as the leptomeninges, include the pia mater and the arachnoid mater that buffer the brain and spinal cord [7]. As indicated in image III below, the subarachnoid space is the area located between the arachnoid mater and the pia mater layers of tissue covering the brain. This anatomic space is occupied by a spongy connective tissue known as trabeculae which spans across the subarachnoid space connecting the two layers of the leptomeninges, providing
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They would diffuse through the cerebrospinal fluid surrounding the brain and circulate through the ventricles and down the spinal column. Within a number of hours following an intracranial haemorrhage, the erythrocytes that leaked into the subarachnoid space migrate through the CSF and begin to haemolyse, releasing their oxyhaemoglobin content into the fluid [11]. This can be detected visually via colour comparisons; however this method only provides a quantitative interpretation of the sample. Instead, the preferred method of CSF oxyhaemoglobin is via spectrophotometric analysis from 4-10 hours following the bleed at a wavelength of 415 nm [12]. The majority of the oxyhaemoglobin is broken down into globin molecules and haem. Through the phagocytic actions of macrophages present in the CSF, the haem is initially broken into biliverdin before the iron compounds are removed, and through degradation by enzymes, the degradation product bilirubin is produced. This pigment is responsible for producing the yellow-brown appearance in positive CSF samples and is detectable at a wavelength of 476 nm. Through oxidation of the haem group, methaemoglobin is sometimes produced after around 10 days following the initial erythrocyte haemolysis [11].
The presence of bilirubin can take up to 12 hours to reveal its color due to the time required to metabolizing oxyhaemoglobin to bilirubin [13]. This is why the lumbar puncture process may be delayed to allow adequate time frames for the presentation of the pigment allowing for a more accurate detection and diagnosis via
They would diffuse through the cerebrospinal fluid surrounding the brain and circulate through the ventricles and down the spinal column. Within a number of hours following an intracranial haemorrhage, the erythrocytes that leaked into the subarachnoid space migrate through the CSF and begin to haemolyse, releasing their oxyhaemoglobin content into the fluid [11]. This can be detected visually via colour comparisons; however this method only provides a quantitative interpretation of the sample. Instead, the preferred method of CSF oxyhaemoglobin is via spectrophotometric analysis from 4-10 hours following the bleed at a wavelength of 415 nm [12]. The majority of the oxyhaemoglobin is broken down into globin molecules and haem. Through the phagocytic actions of macrophages present in the CSF, the haem is initially broken into biliverdin before the iron compounds are removed, and through degradation by enzymes, the degradation product bilirubin is produced. This pigment is responsible for producing the yellow-brown appearance in positive CSF samples and is detectable at a wavelength of 476 nm. Through oxidation of the haem group, methaemoglobin is sometimes produced after around 10 days following the initial erythrocyte haemolysis [11].
The presence of bilirubin can take up to 12 hours to reveal its color due to the time required to metabolizing oxyhaemoglobin to bilirubin [13]. This is why the lumbar puncture process may be delayed to allow adequate time frames for the presentation of the pigment allowing for a more accurate detection and diagnosis via