leptomeningetele

Leptomeninges refers to the two innermost membranes that cover the brain and spinal cord, collectively known as the meninges. These membranes are the arachnoid mater and the pia mater. The arachnoid mater is a thin, web-like layer situated beneath the dura mater, the outermost and toughest meningeal layer. It is characterized by the presence of arachnoid villi which project into the dural venous sinuses, playing a crucial role in cerebrospinal fluid (CSF) reabsorption. Beneath the arachnoid mater lies the subarachnoid space, a cavity filled with CSF. This space is crossed by delicate connective tissue strands, giving the arachnoid mater its name.

The pia mater is the innermost meningeal layer, a delicate and highly vascularized membrane that tightly adheres to the surface of the brain and spinal cord, following all their gyri and sulci. It is so intimately attached that it is considered an extension of the glia limitans. The pia mater contains blood vessels that supply the neural tissue. The space between the arachnoid mater and the pia mater, the subarachnoid space, is where the cerebrospinal fluid circulates. This fluid acts as a cushion, protecting the central nervous system from mechanical shock and also contributes to nutrient and waste transport. Inflammation of the leptomeninges is known as leptomeningitis.