Spinal cord anatomy
Jake Baker and Niamh McCarville
Contents
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Features of spinal cord
Autonomic vs. somatic nervous systems
Comparison of spinal cord segments
Spinal cord blood supply
Anatomy and function of the meninges
Spinal tracts
Spinal cord cross-section
Spinal nerves
Sympathetic chain
Parasympathetic vs.
sympathetic
Comparison of
Spinal Cord
segments
Spinal cord blood supply
Artery: Arch of Aorta -> subclavian artery -> vertebral artery -> spinal arteries
Vein: Subdural plexus of veins -> hemiazygous -> azygous
Meninges
• Subarachnoid space
contains CSF.
Layer of dura
Characteristics
Dura mater
Creates foldings
(tentorium cerebelli,
falx cerebri) which
contain superior
sagittal sinus
Arachnoid
mater
Contains fibroblasts,
collagen
Pia mater
Highly vascularised
The spinal tracts
Spinothalamic
Dorsal column
Corticospinal
Sensations
Affective sensation, pain,
temperature, crude touch
Proprioceptive information and
fine touch
Skilled, voluntary
muscle movement
First-order
First neurone enters spinal
cord at spinal nerve. Cell body
located in dorsal root ganglion
First neurone enters spinal cord
at spinal nerve, forming
Fasciculus Gracilis and
Fasciculus Cuneatus.
Terminate in dorsal column
nuclei in medulla.
Upper Motor
Neurone:
Motor area of
cerebral cortex. Axons
pass through internal
capsule and
brainstem. Desuccate
at pyramids.
Second-order
Axon of second order neurone
crosses over to the other side
and ascends to thalamus
where it terminates.
Second order neurons
desuccate and ascend to
thalamus as a medial lemniscus.
Third-order
Third order neurone has cell
body in thalamus and its axon
projects to somatosensory
cortex
Project from thalamus to
somatosensory cortex (post
central gyrus)
Lower Motor
Neurone:
From spinal cord level
to skeletal muscle
Final destination
Somatosensory cortex
Somatosensory cortex
Skeletal muscle
Site of crossover
Thalamus
Medulla oblongata
Pyramids
Spinal tracts on a spinal cord segment