Anatomy Meninges and Cerebrospinal fluid- Final

Cranial dura mater

-also serves as periosteum -splits sometimes forming venous sinuses and partitions like falx cerebrei

What is the cauda equina?

-bundle of spinal nerves remaining caudally after the end of the spinal cord -Spinal nerves L6-Cd 5 Includes those that form the siatic (L6-S1) and pudendal (S2-3)

Spinal dura mater

-epidural space -between periosteum and dura mater

Dura mater (Pachymaninx)

-relatively thick and fibrous -superficial meningeal layer -tightly attached to the deeper arachnoid

Define Meninges

-the protective envelope for the brain and spinal cord located within the cranium and vertebral canal (neural canal) respectively

What are the 3 inner meninges (leptomeninges)? And their characteristics?

1. Arachnoid membrane -collagenous -arachnoid trabeculae 2. Pia mater -intimately attached to the surface of the brain -the pia mater extends into the depths of various sulci, fissures 3. subarachnoid space- space between arachnoid and pia mater a. forms cisterns of CSF b. cisterna cerebellomedullaris (cisterna magna) c. denticulate ligament- lateral extension through sub arachnoid space

What is CSF?

Cerebrospinal fluid -fluid present in the subarachnoid space around the brain and spinal cord -functions like a lymphatic drainage system for the CNS, which lacks lymph vessels

Where is the cervial intumescence and lumbar intumesence?

Cervical intumescence= brachial plexus (C6-T2) Lumbar Intumescence= lumbosacral plexus (L4-S3) Conus medullaris (caudal tapering end)

Where does the spinal cord end in the dog and cat?

Conus medullaris Dog: L6-L7 Cat: L6-S3

Where is the Denticulate ligament?

Lateral extension through subarachnoid space.

What is the route of CSF flow/drainage?

Produced by Choroid plexus--> ventricular system of the brain and central canal of SC--> subarachnoid space--> drained into dural venous sinuses and lymphatics

What does the arachnoid villi do?

Regulates drainage of CSF into dural venous sinuses

What is the filum termiale/ terminal filament?

thin extension of the spinal cord (only pia mater which is modified) after the end of the spinal cord, surrounded by dura mater

How many spinal nerves?

About 36 C-8 T-13 L-7 S-3 Cd-5

What is the subarachnoid space?

The space between the arachnoid and pia mater. -Forms cisterns of CSF -Cisterna cerebellomedullaris (cisterna magna)