Arachnoid Space

A subarachnoid hemorrhage is bleeding in the space between your brain and the surrounding membrane subarachnoid space.

Arachnoid space. The arachnoid is attached to the dura mater while the pia mater is attached to the central nervous system tissue. The ventral layer of arachnoid membrane on the other hand is a direct anterior extension of this arachnoid envelope that the dorsal layer forms over the pineal region. Widened arachnoid space with anechoic cerebral fluid in a case of benign macrocrania. The headache is sometimes associated with nausea vomiting and a brief loss of consciousness.

The space between the pia mater and the arachnoid mater occasioned by the fact that the pia the innermost layer of the meninges closely invests the surface of the brain while the arachnoid external to it bridges over the grooves. However in the sulci triangular spaces develop because the pia mater is closely applied to the cerebral cortex and the arachnoid membrane bridges the gap between adjacent gyri without descending into each sulcus. Arachnoid cysts are regarded as a developmental anomaly that occur in the subarachnoid space. The subarachnoid space contains blood vessels.

When the dura mater and the arachnoid separate through injury or illness the space between them is the subdural space. The dorsal layer covers internal cerebral veins and fixes them to the surrounding tela choroidea. The subarachnoid space is compartmentalized into cisterns built with sheets of arachnoid tissue and filled with cerebrospinal fluid csf. Over the gyri the arachnoid membrane and pia mater are in close contact.

There are two subdivisions of arachnoid mater surrounding the subarachnoid space the dorsal layer and the ventral layer. This area is called the subarachnoid space. Hemorrhage means bleeding it can happen when an artery is damaged and starts to bleed.