9: Nervous System- Ventricular and Meninges

Comprehensive vocabulary flashcards covering the cranial and spinal meninges, dural structures, cerebrospinal fluid dynamics, and the anatomy of the ventricular system.

Meninges

Three connective tissue membranes (dura mater, arachnoid mater, and pia mater) that envelop the brain and spinal cord.

Dura mater

The fibrous, tough, leathery outer membrane of the meninges that is firmly fixed in place.

Periosteal layer

The outer layer of the cranial dura mater that adheres to the entire inside surface of the skull; it does not exist in the spinal cord.

Meningeal layer

The inner layer of the cranial dura mater that continues into the spinal cord as the spinal dura mater.

Dural venous sinuses

Cavities or channels formed where dural layers separate, collecting venous blood from the brain to direct it into the internal jugular veins.

Superior sagittal sinus

A dural sinus located along the sagittal fissure that collects venous blood and receives cerebrospinal fluid (CSF) re-entering the bloodstream.

Dural septa

Flat partitions formed by inward extensions of the meningeal dural layer that subdivide the cranial cavity and limit brain movement.

Falx cerebri

A dural septum that separates the two cerebral hemispheres.

Falx cerebelli

A dural septum that separates the two cerebellar hemispheres.

Tentorium cerebelli

A dural septum that separates the cerebrum from the cerebellum.

Arachnoid mater

The middle meninx; a loose, elastic membrane deep to the meningeal dura mater and superficial to the pia mater.

Subdural space

A very thin space between the dura mater and arachnoid mater containing a small amount of serous fluid.

Subarachnoid space

The wide space between the arachnoid and pia mater filled with cerebrospinal fluid (CSF) and containing the brain's largest blood vessels.

Arachnoid trabeculae

Spiderweb-like extensions of connective tissue that loosely secure the arachnoid mater to the underlying pia mater.

Arachnoid granulations

Knoblike projections of arachnoid mater that protrude into dural sinuses and act as one-way valves for CSF drainage into venous circulation.

Bridging veins

Veins that drain blood from the cerebral cortex into dural venous sinuses by puncturing the arachnoid and dura mater.

Subdural hemorrhage

Bleeding into the subdural space, often caused by the tearing of bridging veins during forceful acceleration or deceleration of the head.

Pia mater

The deepest meninx; a delicate connective tissue layer with tiny blood vessels that clings tightly to every convolution of the brain.

Epidural space

The space between the spinal dura mater and the vertebral canal walls, filled with adipose tissue and veins.

Denticulate ligaments

Lateral extensions of spinal pia mater that fuse with the arachnoid and dura mater to stabilize the spinal cord.

Filum terminale

A single inferior extension of pia mater that connects the conus medullaris to the coccyx.

Lumbar cistern

A large pocket of subarachnoid space extending from $L2$ to $S2$ containing CSF and the cauda equina; the site for lumbar punctures.

Conus medullaris

The point where the spinal cord ends, typically at the level of the $L1/L2$ vertebrae.

Ventricular system

An interconnected series of cavities (ventricles, canals, and spaces) filled with cerebrospinal fluid that circulates throughout the CNS.

Cerebrospinal fluid (CSF)

A fluid composed mostly of water, solutes, and ions (such as $Na^{+}$, $Cl^{-}$, and $Mg^{2+}$) that provides nutrient exchange and protection for the CNS.

Choroid plexuses

Networks of blood vessels and ependymal cells within the ventricles that produce cerebrospinal fluid.

Lateral ventricles

Paired, large C-shaped cavities located in each cerebral hemisphere, separated by the septum pellucidum.

Interventricular foramen

A short channel on the midline that connects the lateral ventricles to the third ventricle.

Third ventricle

A narrow cavity located on the midline of the diencephalon.

Cerebral aqueduct

A channel running through the midbrain that connects the third ventricle to the fourth ventricle.

Fourth ventricle

A cavity located between the brainstem (pons and medulla) and the cerebellum, continuous with the central canal of the spinal cord.

Lateral and median apertures

Openings in the fourth ventricle that connect the ventricular system to the subarachnoid space.