Examples of arachnoid

• Suprasellar arachnoid cyst compressing the brain stem and bilateral hemispheres.

• They are lined by arachnoid membranes, and filled with fluid which is the same character as the cerebrospinal fluid.

• Any injury to the arachnoid membrane carries a risk of arachnoiditis.

• It does not penetrate the arachnoid membrane, nor is a contrast agent injected, but arachnoiditis has been reported following epidural injections.

• Stems and leaves are finely arachnoid-tomentose becoming glabrous and green with age.

• The dura is opened and the arachnoid incised.

• They arise from the arachnoid cap cells of the arachnoid villi in the meninges.

• The space between the arachnoid and the underlying pia mater is called the subarachnoid space.