A meningocœleThis is a sac-like expansion of the membranes that enclose the brain and spinal cord. It is an abnormality of normal development that is usually evident at birth and surgical correction is usually carried out. It is associated with abnormal development of the bones of the spinal canal, referred to as spina bifida. If there are neural elements inside the meningocœle then the term myelomeningocœle is used. is a congenitalAn abnormality, structural or otherwise, which is present at birth, although its presence may not become evident until later in life, if at all. abnormality (i.e. presenting at birth), consisting of an abnormal sac protruding from some point along the spine of the new-born child, most commonly at its lower end. It is lined by membranes identical to those which line the normal spinal canalThe individual bones that comprise the spinal column are made up of a weight-bearing “body” and other components which, together, form a ring of bone, behind the body. These individual vertebrae, joined together as the spinal column, therefore, create a canal running down the entire length of the spine. (the meningesThese are membranes which enclose the brain and the spinal cord. There are three, which are very different from one another in nature. The dura is the outermost, lining the inside of the skull and the spinal canal. It is tough and waterproof, retaining the cerebrospinal fluid that bathes the brain and spinal cord. The innermost layer is the pia, which is like a thin skin applied closely to the surface of the brain and spinal cord. Between these two layers is the arachnoid, which is a loose, net-like structure made up of sheets and strands of thin, translucent material, stretching between the dura and the pia. The cerebrospinal fluid flows along the subarachnoid channels, between the arachnoid and the...) and is filled with cerebrospinal fluidThis clear, water-like fluid forms, for the most part, within the brain, more specifically inside the ventricles of the brain. Blood flows through structures inside the ventricles, called the choroid plexuses, and clear fluid is produced as a result, passing into the ventricle. This process is akin to blood flowing through the kidneys and urine being produced as a result. An important difference is that, unlike urine, the cerebrospinal fluid is not passed out of the body periodically. Instead, the fluid is re-absorbed back into the blood stream, mostly via the arachnoid granulations, into the cerebral venous sinuses. In the course of a 24-hour period, most healthy adults will produce about 500mls (or a pint) of cerebrospinal fluid, although at.... It may also contain a segment of abnormally developed spinal cordThe main nerve trunk running down the spinal canal and connecting the individual’s mind and consciousness to the rest of his or her body. It is about the size of a person’s little finger, in diameter. It cannot repair itself if damaged., in which case the term myelomeningocœleSee meningocœle. is used. Both meningocœles and myelomeningocœles are, therefore, naturally occurring malformations. When, however, abnormal collections of cerebrospinal fluidThis clear, water-like fluid forms, for the most part, within the brain, more specifically inside the ventricles of the brain. Blood flows through structures inside the ventricles, called the choroid plexuses, and clear fluid is produced as a result, passing into the ventricle. This process is akin to blood flowing through the kidneys and urine being produced as a result. An important difference is that, unlike urine, the cerebrospinal fluid is not passed out of the body periodically. Instead, the fluid is re-absorbed back into the blood stream, mostly via the arachnoid granulations, into the cerebral venous sinuses. In the course of a 24-hour period, most healthy adults will produce about 500mls (or a pint) of cerebrospinal fluid, although at... build-up following a neurosurgical operation, we use the term pseudomeningocœle to describe them. Pseudomeningocœles develop, not uncommonly, after craniovertebral decompressionA surgical operation which aims to expand the internal dimensions of the craniovertebral junction and, thereby, relieve compression of the neural elements within, and/or to improve the flow of cerebrospinal fluid across the craniovertebral junction. for Chiari malformations. When cerebrospinal fluidThis clear, water-like fluid forms, for the most part, within the brain, more specifically inside the ventricles of the brain. Blood flows through structures inside the ventricles, called the choroid plexuses, and clear fluid is produced as a result, passing into the ventricle. This process is akin to blood flowing through the kidneys and urine being produced as a result. An important difference is that, unlike urine, the cerebrospinal fluid is not passed out of the body periodically. Instead, the fluid is re-absorbed back into the blood stream, mostly via the arachnoid granulations, into the cerebral venous sinuses. In the course of a 24-hour period, most healthy adults will produce about 500mls (or a pint) of cerebrospinal fluid, although at... shuntA shunt shifts one object, or volume of fluid (or gas or electrical current), from one place to another. In the context of neurosurgical practice we are considering cerebrospinal fluid, which is diverted from the ventricles of the brain, or the spinal theca, into another part of the body, most often the peritoneal cavity. catheters become displaced from the peritoneal cavitySee peritoneum., a pseudomeningocœle may develop under the skin overlying the abdominal wall.