14.2 Spinal Meninges

• Vertebral column isolates spinal cord from external environment. Delicate neural tissues also must be protected from surrounding vertebral canal. Specialized membranes known as spinal meninges provide protection, physical stability, shock absorption for spinal cord
• Spinal meninges cover and protect spinal cord and spinal nerve roots
• Blood vessels branching within meninges deliver oxygen and nutrients to cord
• At foramen magnum, spinal meninges continuous with cranial meninges surrounding brain
• Three meningeal layers: dura mater, arachnoid mater, pia mater
• The Dura Mater. Consists of dense irregular connective tissue
• The Dura Mater. Simple squamous epithelium covers inner/outer surfaces of dura mater
• The Dura Mater. Outer epithelium not attached to bony walls of vertebral canal, space is epidural space
• The Dura Mater. Epidural space contains areolar tissue, blood vessels, adipose tissue 
• The Dura Mater. Dura mater attached to edge of foramen magnum, 2nd + 3rd cervical vertebrae, sacrum, posterior longitudinal ligament
• The Dura Mater. Attachments stabilize cord within vertebral canal
• The Dura Mater. Spinal dura mater forms dense cord of collagen fibers that blend with filum terminale, forming coccygeal ligament
• The Dura Mater. Extends length of sacral canal and fuses with periosteum of sacrum and coccyx
• The Arachnoid Mater. In a cadaver, narrow subdural space separated dura mater from deeper meninges of spinal cord
• The Arachnoid Mater. In living person, no subdural space
• The Arachnoid Mater. Inner surface of dura lined by outer surface of arachnoid mater
• The Arachnoid Mater. Subarachnoid space separated arachnoid mater from innermost later, pia mater
• The Arachnoid Mater. Contains cerebrospinal fluid (CSF), a shock absorber and diffusion medium for dissolved gasses, nutrients, chemical messengers, wastes
• The Arachnoid Mater. Bundles of fibers, arachnoid trabeculae, extend from inner surface of arachnoid mater to outer surface of pia mater
• The Pia Mater. Deep to the subarachnoid space, innermost meningeal layer
• The Pia Mater. Elastic and collagen fibers of pia mater interwoven with those of arachnoid trabeculae
• The Pia Mater. Blood vessels supplying spinal cord found here
• The Pia Mater. Pia mater firmly bound to underlying neural tissue, conforming to bulges and fissures
• The Pia Mater. Surface of spinal cord consists of thin layer of astrocytes, cytoplasmic extensions of neuroglia lock collagen fibers of spinal pia mater in place
• The Pia Mater. Paired denticulate ligaments located along length of spinal cord
• The Pia Mater. Denticulate ligaments found between dorsal and central roots of spinal nerves
• The Pia Mater. Denticulate ligaments are extension of spinal pia mater
• The Pia Mater. Denticulate ligaments connect pia mater and arachnoid mater to dura mater of spinal cord
• The Pia Mater. Denticulate ligaments begin at foramen magnum
• The Pia Mater. Prevent side to side and downward movement spinal cord 
• The Pia Mater. Connective tissue fibers here form filum terminale
• Spinal meninges surround dorsal and ventral roots of spinal nerves
• Identify the location of the cerebrospinal fluid that surrounds the spinal cord.

  The subarachnoid space between the arachnoid mater and pia mater contains the cerebrospinal fluid.
• List the three meninges that cover the spinal cord and the spinal nerve roots in order from deep to superficial. 

  From deep to superficial, pia mater, arachnoid mater, dura mater.