Lamina terminalis | |
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![]() Median sagittal section of brain of human embryo of three months. (Lamina terminalis labeled at center left.) | |
![]() Median sagittal section of brain of human embryo of four months. (Lamina terminalis labeled at center right.) | |
Details | |
Identifiers | |
Latin | lamina terminalis |
NeuroNames | 208 |
TA98 | A14.1.08.419 |
TA2 | 5776 |
FMA | 61975 |
Anatomical terms of neuroanatomy |
The median portion of the wall of the forebrain consists of a thin lamina, the lamina terminalis, which stretches from the interventricular foramen (foramen of Monro) to the recess at the base of the optic stalk (optic nerve) and contains the vascular organ of the lamina terminalis, which regulates the osmotic concentration of the blood. The lamina terminalis is immediately anterior to the tuber cinereum; together they form the pituitary stalk.
The lamina terminalis can be opened via endoscopic neurosurgery in an attempt to create a path that cerebrospinal fluid can flow through when a person has hydrocephalus and when it is not possible to perform an endoscopic third ventriculostomy, [1] but the effectiveness of this technique is not certain. [2]
This is the rostral end (tip) of the neural tube (embryological central nervous system) in the early weeks of development. Failure of the lamina terminalis to close properly at this stage of development will result in anencephaly or meroencephaly.
Hydrocephalus is a condition in which an accumulation of cerebrospinal fluid (CSF) occurs within the brain. This typically causes increased pressure inside the skull. Older people may have headaches, double vision, poor balance, urinary incontinence, personality changes, or mental impairment. In babies, it may be seen as a rapid increase in head size. Other symptoms may include vomiting, sleepiness, seizures, and downward pointing of the eyes.
Chiari malformation (CM) is a structural defect in the cerebellum, characterized by a downward displacement of one or both cerebellar tonsils through the foramen magnum. CMs can cause headaches, difficulty swallowing, vomiting, dizziness, neck pain, unsteady gait, poor hand coordination, numbness and tingling of the hands and feet, and speech problems. Less often, people may experience ringing or buzzing in the ears, weakness, slow heart rhythm, or fast heart rhythm, curvature of the spine (scoliosis) related to spinal cord impairment, abnormal breathing, such as central sleep apnea, characterized by periods of breathing cessation during sleep, and, in severe cases, paralysis.
Scaphocephaly, or sagittal craniosynostosis, is a type of cephalic disorder which occurs when there is a premature fusion of the sagittal suture. Premature closure results in limited lateral expansion of the skull resulting in a characteristic long, narrow head. The skull base is typically spared.
The pineal gland is a small endocrine gland in the brain of most vertebrates. In the darkness the pineal gland produces melatonin, a serotonin-derived hormone, which modulates sleep patterns following the diurnal cycles. The shape of the gland resembles a pine cone, which gives it its name. The pineal gland is located in the epithalamus, near the center of the brain, between the two hemispheres, tucked in a groove where the two halves of the thalamus join. It is one of the neuroendocrine secretory circumventricular organs in which capillaries are mostly permeable to solutes in the blood.
The third ventricle is one of the four connected ventricles of the ventricular system within the mammalian brain. It is a slit-like cavity formed in the diencephalon between the two thalami, in the midline between the right and left lateral ventricles, and is filled with cerebrospinal fluid (CSF).
The median aperture is an opening of the fourth ventricle at the caudal portion of the roof of the fourth ventricle. It allows flow of cerebrospinal fluid (CSF) from the fourth ventricle into the cisterna magna. The other two openings of the fourth ventricle are the lateral apertures - one on either side. Nonetheless, the median aperture accounts for most of the outflow of CSF out of the fourth ventricle. The median aperture varies in size.
In the brain, the interventricular foramina are channels that connect the paired lateral ventricles with the third ventricle at the midline of the brain. As channels, they allow cerebrospinal fluid (CSF) produced in the lateral ventricles to reach the third ventricle and then the rest of the brain's ventricular system. The walls of the interventricular foramina also contain choroid plexus, a specialized CSF-producing structure, that is continuous with that of the lateral and third ventricles above and below it.
The pituitary stalk, also known as the infundibular stalk, Fenderson's funnel, or the hypothalamo-(neuro)hypophyseal tract, is the connection between the hypothalamus and the neurohypophysis. The floor of the third ventricle is prolonged downward as a funnel-shaped recess—the infundibular recess—into the infundibulum, where the apex of the pituitary is attached. It passes through the dura mater of the diaphragma sellae as it carries axons from the magnocellular neurosecretory cells of the hypothalamus down to the posterior pituitary where they release their neurohypophysial hormones, oxytocin and vasopressin, into the blood.
A craniopharyngioma is a rare type of brain tumor derived from pituitary gland embryonic tissue that occurs most commonly in children, but also affects adults. It may present at any age, even in the prenatal and neonatal periods, but peak incidence rates are childhood-onset at 5–14 years and adult-onset at 50–74 years. People may present with bitemporal inferior quadrantanopia leading to bitemporal hemianopsia, as the tumor may compress the optic chiasm. It has a point prevalence around two per 1,000,000. Craniopharyngiomas are distinct from Rathke's cleft tumours and intrasellar arachnoid cysts.
The cavernous sinus within the human head is one of the dural venous sinuses creating a cavity called the lateral sellar compartment bordered by the temporal bone of the skull and the sphenoid bone, lateral to the sella turcica.
The vascular organ of lamina terminalis (VOLT), organum vasculosum of the lamina terminalis(OVLT), or supraoptic crest is one of the four sensory circumventricular organs of the brain, the others being the subfornical organ, the median eminence, and the area postrema in the brainstem.
Circumventricular organs (CVOs) are structures in the brain characterized by their extensive and highly permeable capillaries, unlike those in the rest of the brain where there exists a blood–brain barrier (BBB) at the capillary level. Although the term "circumventricular organs" was originally proposed in 1958 by Austrian anatomist Helmut O. Hofer concerning structures around the brain ventricular system, the penetration of blood-borne dyes into small specific CVO regions was discovered in the early 20th century. The permeable CVOs enabling rapid neurohumoral exchange include the subfornical organ (SFO), the area postrema (AP), the vascular organ of lamina terminalis, the median eminence, the pituitary neural lobe, and the pineal gland.
The tuber cinereum is the portion of hypothalamus forming the floor of the third ventricle situated between the optic chiasm, and the mammillary bodies. The tuberal region is one of the three regions of the hypothalamus, the other two being the chiasmatic region and the mamillary region.
The hypophyseal portal system is a system of blood vessels in the microcirculation at the base of the brain, connecting the hypothalamus with the anterior pituitary. Its main function is to quickly transport and exchange hormones between the hypothalamus arcuate nucleus and anterior pituitary gland. The capillaries in the portal system are fenestrated which allows a rapid exchange between the hypothalamus and the pituitary. The main hormones transported by the system include gonadotropin-releasing hormone, corticotropin-releasing hormone, growth hormone–releasing hormone, and thyrotropin-releasing hormone.
Endoscopic third ventriculostomy (ETV) is a surgical procedure for treatment of hydrocephalus in which an opening is created in the floor of the third ventricle using an endoscope placed within the ventricular system through a burr hole. This allows the cerebrospinal fluid to flow directly to the basal cisterns, bypassing the obstruction. Specifically, the opening is created in the translucent tuber cinereum on the third ventricular floor.
Karin Marie Muraszko is an American pediatric neurosurgeon.
Aqueductal stenosis is a narrowing of the aqueduct of Sylvius which blocks the flow of cerebrospinal fluid (CSF) in the ventricular system. Blockage of the aqueduct can lead to hydrocephalus, specifically as a common cause of congenital and/or obstructive hydrocephalus.
Endoscopic endonasal surgery is a minimally invasive technique used mainly in neurosurgery and otolaryngology. A neurosurgeon or an otolaryngologist, using an endoscope that is entered through the nose, fixes or removes brain defects or tumors in the anterior skull base. Normally an otolaryngologist performs the initial stage of surgery through the nasal cavity and sphenoid bone; a neurosurgeon performs the rest of the surgery involving drilling into any cavities containing a neural organ such as the pituitary gland. The use of endoscope was first introduced in Transsphenoidal Pituitary Surgery by R Jankowsky, J Auque, C Simon et al. in 1992 G.
Sandi Lam is a Canadian pediatric neurosurgeon and is known for her research in minimally invasive endoscopic hemispherectomy for patients with epilepsy. Lam is the Vice Chair for Pediatric Neurological Surgery at Northwestern University and the Division Chief of Pediatric Neurosurgery at Lurie Children's Hospital. She has spent her career advancing pediatric brain surgery capabilities globally through her work in Kenya performing surgeries as well as training and mentoring local residents and fellows.
This article incorporates text in the public domain from page 816 of the 20th edition of Gray's Anatomy (1918)