Dalley, 10th Edition

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Contents of Vertebral Canal

Dura–arachnoid interface [subdural (potential) “space”] —schematically exaggerated; see note in table

Posterior spinal arteries

Periosteum covering surface of compact bone

Internal vertebral venous plexus

Extradural (epidural) space occupied by fat

Arachnoid mater

Posterior root Spinal dural sac

2

Spinal nerve

Intervertebral foramen (above pedicle)

Intervertebral vein

Arachnoid trabeculae

Anterior spinal artery

Anterior root

Pia mater

Denticulate ligament (pia mater)

Spinal dura mater

Vertebral body

Schematic, transverse section

CSF in subarachnoid space

Spinal cord

FIGURE 2.49. Transverse section of spinal cord in situ demonstrating meninges and associated spaces.

TABLE 2.15. SPACES ASSOCIATED WITH SPINAL MENINGES a Space Location

Contents

Epidural

Space between periosteum lining bony wall of vertebral canal and spinal dura mater

Fat (loose connective tissue); internal vertebral venous plexuses; inferior to L2 vertebra, ensheathed roots of spinal nerves

Subarachnoid (leptomeningeal) Naturally occurring space between arachnoid mater and pia mater Copyright © 2027 Wolters Kluwer. Unauthorized reproduction of the article is prohibited. CSF; radicular, segmental, medullary, and spinal arteries; veins; arachnoid trabeculae

a Although it is common to refer to a “subdural space,” there is no naturally occurring space at the dura–arachnoid junction (Haines & Willis, 2025).

arachnoid trabeculae , span the subarachnoid space con necting the spinal arachnoid and pia.

(Haines & Willis, 2025). Bleeding into this layer creates a pathological space at the dura–arachnoid junction in which a subdural hematoma is formed. In the cadaver, because of the absence of CSF, the spinal arachnoid falls away from the inner surface of the dura and lies loosely on the spinal cord. The spinal arachnoid is separated from the pia mater on the surface of the spinal cord by the subarachnoid space containing CSF. Delicate strands of connective tissue, the

SPINAL PIA MATER The spinal pia mater , the innermost covering membrane of the spinal cord, is thin and transparent and closely follows all the surface features of the spinal cord. The spinal pia also