Spinal Cord Flashcards
Function and length of spinal cord
F: Nerve impulse propagation
A: Extends from medulla and foramen magnum to conus medullaris L1-2 IV joint
-cauda equina L2-S5 (PNS)
Spinal Nerves
31 paired spinal nerves
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal
What are the 2 enlargements of the spinal cord?
cervical
-C5-T1: brachial plexus
lumbar
-T11-L2: lumbosacral plexus
Meninges
Epidural space Dura mater Subdural space Arachnoid mater Subarachnoid space Pia mater
Epidural space
“Cushion” composed of fatty tissue, lymphatics, blood vessels, nerve roots
Dura mater
single layer of fibrous tissue
- anchor for peripheral nerves to SC
- extends to S2 vertebral level
Subdural space
interstitial fluid
Subarachnoid space
contains CSF
-spinal tap takes place here
Pia mater
Filum terminale= fibrous extension of pia at the end of conus medullaris
-anchors SC to coccyx
Basic SC anatomy
Composed of gray (inside) and white (outside) matter
Gray matter anatomy
dorsal horn= sensory neurons
intermediate zone= interneurons
-T1-L2: lateral horn (symp. pregang neurons)
-S2-S4: lateral horn (para. pregang neurons)
ventral horn= motor neurons
-somatotopically organized
White matter ascending and descending columns
- dorsal column= sensory fibers (ascending)
- ventral column=mixed (primarily motor)
- lateral column= mixed
- some somatotopically organized, others not
White matter sulci, septum, and fissure
Dorsolateral sulcus: entrance for dorsal roots
Dorsal intermediate sulcus: splits dorsal columns into fasciculi cuneatus and gracilis
Ventral lateral sulcus: exit for ventral roots
Dorsal median septum: sheet of glial cells folded inwards
-Turns to dorsal median sulcus in caudal SC
Ventral median fissure: fold in pia mater
-Anterior spinal artery
Structural differences between different levels of the SC
white matter increases from lumbosacral –> cervical
-exception: cranial enlargement
volume of gray matter is highest in cervical and lumbar enlargements
