Spinal Meninges

Dr. Rajesh T Dept. of Anatomy MMMC, Manipal University

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• Coverings of spinal cord

Dura mater

Arachnoid mater

Pia mater

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Spinal Dura mater

• Loose envelope, consists of only meningeal layer

Extent

- Margin of foramen magnum to lower border of second sacral vertebra

- caudally incorporates with the filum terminale- periosteum of coccygeal vertebra

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Spinal dura – provides tubular prolongations around the roots of the spinal nerves

Extend through intervertebral foramina along the spinal nerves for variable distance

Sensory innervation- recurrent branches of spinal nerves

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Epidural Space

• Space b/w spinal dura and the periosteum of vertebral column

• Extends from foramen magnum to sacral hiatus

• Bilaterally upto intervertebral foramina

Contents

Fat, loose areolar tissue

Internal venous plexus

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Internal Venous plexus

• Valveless

• Blood flow not affected by intra-thoracic or intra-abdominal pressure

• Communicates- caval and azygos system of veins, veins from prostate, mammary and thyroid glands

• Occasional metastasis to vertebral bodies in carcinoma of prostate

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• Epidural anasthesia

To produce segmental and regional anasthesia- anasthetic fluid introduced in the epidural space

Eg. During child birth

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Spinal Arachnoid

• Envelopes loosely

• Along with subarachnoid space it extends upto second sacral vertebra

• Also invests root of spinal nerves

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Spinal Cistern

• A wide space distal to caudal end of spinal cord

• Intervene b/w lower borders of L1 and S2 vertebrae

• It contain- CSF, rootlets of cauda equina and filum terminale.

Applied aspects:

• Lumbar puncture - CSF aspiration b/w L3 and L4, since it does not damage the spinal cord

• Injury to fibers of cauda equina- chance of regeneration

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Lumbar Puncture – lumbar (terminal) cistern

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Spinal Pia mater

• Thicker and less vascular than cerebral pia

• Completely invests spinal cord, enters as reticular core through anterior median fissure

• Extends as tubular sheath around rootlets of spinal nerves upto intervertebral foramina

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• Special Features

Filum terminale

Linea Splendens

Ligamentum Denticulatum

Subarachnoid Septum

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Filum Terminale

• Non-nervous filamentous thread about 20 cm long

Attachments

Cranial: tip of the conus medullaris of spinal cord at lower border of L1.

Pierces dura & arachnoid – at the level of S2

Leaves Haitus sacralis

Caudal: Periosteum of posterior surface of First coccygeal vertebra

Terminal ventricle- part of central canal in upper 5 or 6 mm of filum terminale

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Linea Splendens

• It is a median glistening line on the ventral surface of the lower part of spinal cord along the anterior median fissure.

• It continuous below with filum terminale

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Ligamentum Denticulatum

• Coronally oriented pial sheet

• 21 serially arranged triangular teeth-like processes.

• Extend bilaterally from side of spinal cord b/w the ventral and dorsal roots of the spinal nerves

• Attached to the dura mater for better anchorage of spinal cord

• 1st process is attached to the margin of foramen magnum

• Last process- b/w roots of 12 thoracic nerve and 1st lumbar nerve

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Subarachnoid Septum

• Is a mid-sagittal pial sheet extending from arachnoid to dorsal surface of the spinal cord along the posterior median sulcus

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