Search results for "Pia Mater"
showing 5 items of 5 documents
Do spinal meningiomas penetrate the pial layer? Correlation between magnetic resonance imaging and microsurgical findings and intracranial tumor inte…
1997
OBJECTIVE: To study the relationships between spinal dura-arachnoid and tumor-cord interfaces in spinal meningiomas and to investigate whether a disruption of the pial layer and penetration of the tumor in the spinal cord occurs. METHODS: Fifteen patients with histologically proven meningiomas underwent magnetic resonance imaging (MRI) preoperatively. All patients underwent microsurgery. The histological characteristics of the tumors were compared with MRI and microsurgical findings. RESULTS: At surgery, the peritumoral hypointense rim revealed by MRI in 10 of 15 patients corresponded to a well-defined cerebrospinal fluid-containing space confined between the outer arachnoidal layer and the…
The pia mater at the site of the entry of blood vessels into the central nervous system
1982
The entry of blood vessels into the central nervous system (CNS) has been studied at the surface of the brain stem and the spinal cord of two cats and two rabbits. The study was carried out by scanning electron microscopy (SEM). The results obtained by SEM concerning the layers of the pia mater corresponded to those obtained by other authors who used transmission electron microscopy. Between the basal lamina of the superficial glial membrane of the CNS and the cells lining the subarachnoid space, a pial connective tissue space could be clearly recognized. The blood vessles crossing the subarachnoid space were also covered by leptomeningeal lining cells. At the site of entry of these blood v…
Ultrastructure of Spinal Dura Mater
2014
Pia mater is the innermost of the three meningeal membranes, closely surrounding the brain, the spinal cord, and the portion of spinal nerve roots extending towards their exit across the dura mater. A cellular layer and a subpial compartment shape the structure of the pia mater. The cellular layer is made up of flat, overlapping pial cells with amorphous, fundamental substance interposed among them. The surface of the cellular plane appears smooth and bright under scanning electron microscopy (SEM). Transmission electron microscopy shows that the cellular component is about three to five pial cells thick at the medullary level and two to three cells thick at the level of the nerve roots. Th…
Ultrastructure of Human Spinal Trabecular Arachnoid
2014
The arachnoid trabecular layer, located internally to the arachnoid layer, is composed of fibers that form the spider web–like trabecular structure found in the subarachnoid space and in the adventitial layer of blood vessels. The arachnoid trabeculae give shape to tubular structures (arachnoid sheaths) for each nerve root and for the spinal cord. Some of these arachnoid trabeculae extend to the pia mater. The trabecular arachnoid is an extremely fragile structure, which can easily be damaged. Because of its fragility, this membrane may be destroyed during dissection and manipulation, so that it is not frequently seen or systematically described. Trabecular arachnoid limits nerve root movem…
Leukodiapedesis and leukocyte migration in the leptomeninges and in the subarachnoid space.
1981
Pleocytosis in cerebrospinal fluid and infiltration of the leptomeningeal tissue have been studied after injection of ferritin into the subarachnoid space (SAS) of cats. The most important source of granulocytes in the leptomeninges are the relatively large veins of the pia mater, which have very thin walls. Passing between the lining cells of the pia mater the granulocytes leave the connective tissue space of the pia mater and reach the SAS. Leukodiapedesis has also been observed in veins crossing the SAS. During this process, gaps between the lining cells of the perivascular leptomeningeal sheath may develop. There are two possible ways for the granulocytes to pass from the vascular pia m…