Class 1 Flashcards
Layers of meninges
Dura mater
Arachnoid mater
Pia mater
Meninges
Second protective structure after skull/vertebrae.
Epidural space
Between dura mater and vertebrae
Contains fat and connective tissue.
Dura mater
Most superficial layer of the meninges
Thick and strong.
Made of dense irregular connective tissue.
Runs from Foramen Magnum to s2
Continuous with epineurum of nerves
Subdural space
Theoretical space between dura mater and arachnoid mater. Contains (minute quantities) of interstitial fluid.
Arachnoid mater
Middle layer of meninges
Loosely arranged collagen and elastic fibres.
Subarachnoid space
Between arachnoid and pia mater b
Contains CSF
Pia mater
Deepest, thinnest layer of meninges
Squamous –> cuboidal cells
Contains blood supply to spinal cord.
Denticulate ligaments.
Thickenings of pia mater.
Fuse with arachnoid and inner dura mater
Anchor spinal cord to vertenbrae
Diameter of spinal cord
1.5 cm
Length of spinal cord
Medulla oblongata to superior L2 (in adults; L3-4 in neonates)
Cervical enlargement of spinal cord
C4-T1 (nerves to/from upper limbs)
Lumbar enlargement of spinal cord
T9-12 (nerves to/from lower limbs)
Conus medullaris
Terminis of spinal cord
Inferior to lumbar enlargment
IVD between L1-2
Filum terminale
Anchors spinal cord to coccyx
Extension of pia mater (fused with arachnoid and dura mater)
Cauda equina
Inferiorly angled nerves exiting in the space between conus medullaris and end of vertebral column.
Peripheral: nerve
Central:
Tract
Peripheral: ganglia
Central:
Nuclei
- basal ganglia in brain is a nuclei not a ganglion *
Ganglia/Nuclei
Clusters of cell bodies
Tracts/nerves
Bundles of axons.
Rootlet
Small bundle of axons connecting nerve roots to spinal cord.
Roots
Larger bundles of axons connecting spinal nerves to segments of cord via rootlets
Posterior (dorsal) root
Axons of sensory neurons.
Dorsal root ganglion
Enlargement containing sensory cell bodies
Ventral (anterior) root
Motor nerves.
White matter
Mostly myelinated bundles of axon sheaths
In Peripheral Nervous system, superficial to grey matter
Grey matter
Unmyelinated axons, neuroglia, dendrites and cell bodies
In PNS deep to white matter
Postior median sulcus
Dent in centre posterior spinal cord.
Grey Commisure
Connects two halves of spinal cord.
Central canal of spinal cord
Contains CSF
Anterior median sulcus
More of a fissure. Big dent in anterior spinal cord
Anterior/posterior white commisure
Connect white matter on R & L
Posterior grey horns
Incoming sensory neurons
Anterior grey horns
Somatic motor neurons.
Lateral grey horns
Only in T spine and upper L spine.
Autonomic motor nuclei (regulate cardiac, smooth muscle, glands)
Anterior/posterior/lateral white columns
Each column contains distinct bundles of axons with a common origin or destination and carrying similar info.
Three coverings of spinal nerves
Endoneurium
Perineurium
Epineurium
Endoneurium
Innermost layer. Wraps individual axons.
Perineurium
Middle layer. Wraps fascicles (bundles of axons in endoneurium)
Epineurium
Outer layer. Wraps entire nerve.
Rami
The branches divided into by the spinal nerves after exiting intervertebral foramen
Dorsal Ramus
Serves muscles and skin of posterior trunk
Ventral ramus
Serves muscles and structures of limbs, and skin of anterior and lateral trunk.
Meningeal branch
Ramus.
Reenters vertebral canal to supply vertebrae, vertebral ligaments, blood vessels of the spine, and meninges.
Rami communicante
Serves autonomic nervous system
Four plexuses
Cervical
Brachial
Lumbar
Sacral
Intercostal Nerves
T2-12
Neuropraxia
1st degree nerve injury
Mild focal compression.
Segmental demyelination
No break in fibre; reversible in hours to months
Motor function loss
Axonotmesis
2nd degree nerve injury
Prolonged, severe compression
Endoneurium intact
Wallerian degeneration
Sensory, motor and autonomic loss
Reversible in less than 6 months
Neurotmesis
3rd degree nerve injury
Damaged Endoneurium
Wallerian degeneration
Difficult to regenerate – scar tissue, edema, bleeding
Wallerian degeneration
Degeneration of axon distal to injury
Nociceptors
Pain receptors
Alpha and beta fibres
Small, myelinated, fast and well localized
C fibres
Unmyelinated
Smaller, slow.
Poorly localized, burning/throbbing pain