November 2015
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Objective:
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To describe the anatomy and physiology of the spinal cord
To list and describe the function of the protective coverings
found around the spinal cord
Journal:
What do you think the function of the spinal cord is?
Spinal Cord
Spinal Cord
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Neural information superhighway that runs inside your
vertebral column to the foramen magnum
Runs from the the second lumbar vertebrae to the brain
stem
Made up of 31 segments each with a pair of spinal nerves
Spinal Cord Nerve Names
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Named for their corresponding vertebrae
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Cervical Nerves: C1 – C8
Thoracic Nerves: T1 – T12
Lumbar Nerves: L1 – L5
Sacral Nerves: S1 – S5
Coccygeal Nerve located at the coccyx
Spinal Cord External Anatomy
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Spinal cord ends at L2 at the conus
medullaris
Hanging from the conus medullaris
is the cauda equina (“Horse Tail”),
which is a bunch of spinal nerves
that hang from the L2 spinal
nerves to the coccygeal nerve in a
bath of cerebrospinal fluid
Meninges
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Series of protective membranes within the bone that
cover the brain and spinal cord
Help set up the layers of cushioning and shock absorbers
for the brain and spinal cord
Layers of Protection around the CNS
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Vertebrae
Epidural space
Dura mater
Subdural space
Arachnoid mater
Subarachnoid space
Pia mater
Spinal Cord
Epidural Space
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Found between the dura mater and vertebrae
Filled with fat and blood vessels
Dura Mater
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Outer layer of the meninges, closest to the bone
Made of thick, fibrous tissue
Subdural Space
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found between the dura mater and the arachnoid mater
Filled with cerebrospinal fluid
Arachnoid Mater
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Middle meninge layer
Made of a delicate layer of
collagen and elastic fibers
surrounded by
cerebrospinal fluid
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Acts as a shock absorber
Can transport nutrients,
dissolved gases,
neurotransmitters and waste
Contain arachnoid villi
Subarachnoid Space
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Found between the arachnoid mater and the pia mater
Cerebrospinal fluid cushioning for the CNS
Pia mater
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Meninge layer fused to the neural tissue of the CNS
Contains blood vessels that supply blood to the brain and
spinal cord
Spinal Cord Internal Anatomy
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Anterior Medial Fissure: deep groove on the CNS
Posterior Median Sulcus: shallow groove on the CNS
Gray Matter Horns
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Cell body regions that are unmyelinated
Three Types:
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Dorsal Horns: Involved in sensory functions
Ventral Horns: Involved in motor functions
Lateral Horns: Involved in autonomic functions
White Matter Columns
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Nerve tracts (similar to axons) that run up and down the
spinal cord, to and from the brain
Like communication wires that transport information
Spine Extending to Nerves
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Central Canal: cavity in the
center of the spinal cord that
is filled with cerebrospinal fluid
Spinal Roots: project from the
spinal cord in pairs and then
fuse to form spinal nerves
Dorsal Root Ganglion: carries
sensory information
Ventral Root Ganglion: carries
motor information
Spinal Nerves: carries both
sensory and motor
information from the body to
the spinal cord
Plexus
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Complex branching patterns that extend from the spinal
cord to peripheral structures
Types
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Nerves C1 to C4 supply the skin and muscles in the neck,
shoulders, and diaphragm
Nerves C5 to C8 & T1 supplies the upper extremities
Nerves T12, L1-L5, and S1-S4 supplies the skin and muscles of the
abdominal wall & lower extremities