arachnoidal granulations

a·rach·noid gran·u·la·tions

[TA]

tufted prolongations of pia-arachnoid, composed of numerous arachnoid villi that penetrate dural venous sinuses and effect transfer of cerebrospinal fluid to the venous system. In older people, these are more numerous and tend to calcify.

Synonym(s): arachnoidal granulations [TA], granulationes arachnoideae [TA], pacchionian bodies, pacchionian corpuscles, pacchionian glands, pacchionian granulations

Farlex Partner Medical Dictionary © Farlex 2012

arachnoidal granulations

Projections of the middle (ARACHNOID) layer of the MENINGES through the dura mater into the cerebral veins. The arachnoid granulations are the site of reabsorption of cerebrospinal fluid (CSF) into the blood. Failure of CSF to reach them leads to HYDROCEPHALUS. They are also known as arachnoid villi or Pacchionian bodies.

Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005