44 terms

Anatomy: Spinal Cord

Termination in adults
L2 vertebrae
newborns terminate lower
Length of spinal cord
varies depending on height
Cervical and Lumbar Enlargements
where spinal cord is larger in diameter in these regions
Anterior Horn
where motor neurons originate
axons go out to spinal nerves
Ventral and Anterior horns larger in
lower cervical and lower lumbar regions
corresponds to cervical and lumbar enlargements
Nerve Rootlets
originate from ventral(ventral rootlets) and dorsal (dorsal rootlets) surfaces
merge to form dorsal and ventral spinal nerve rootlets
Conus Medularis
terminal portion of the spinal cord
Cauda Equina
large collection of nerve roots on both sides of conus medularis
Filum Terminal
consists of pia mater-not nerve tissue
3 layers of meninges
pia mater, arachnoid membrane, and dura mater
Pia Mater
gentle mother
adhered tightly to the spinal cord
can't pull it off
forms outer layer of spinal cord
Filum terminale
formed by pia mater and the inferior end of the spinal cord
remnant of the caudal part of spinal cord that was in the embryo
Denticulate ligaments
lateral extensions of the pia mater
attach to the inner surface of the dura mater
anchor the spinal cord to the dura mater
Arachnoid Membrane
consists of two layers of tissue
inner and outer layer
extends to S2
Inner layer of Arachnoid Membrane
gives way to fibers that pass to the pia mater
traversing the sub arachnoid space
Outer layer of Arachnoid Membrane
in physical contact with the dura mater
Subarachnoid Space
located between the arachnoid membrane and pia mater
contains CSF
extends from cranial cavity to S2
continuous with cranial subarachnoid space
Dura Mater
tough mother
lies directly on surface of arachnoid membrane (no space between, not attached)
continuous with cranial dura mater
extends to S2
composed of tough collagenous tissue
Subdural Space
occurs in pathological situations
Epidural Space
contains internal vertebral venous plexus embedded in a fatty matrix(epidural fat)
extends from foramen magnum to sacrum
Spinal Nerves
31 pairs
8 pairs cervical, 12 thoracic, 5 lumbar, 5 sacral, & 1 coccygeal
area of skin supplied by one pair of spinal nerves
usually overlap each other
Blood Supply to Spinal Cord
3 arteries run length of spinal cord
2 posterior and 1 anterior
very small
supplemented with other arteries
Anterior Spinal Artery
formed from union of 2 anterior spinal branches of the 2 vertebral arteries
descends to conus medullaris
Posterior Spinal Arteries
branches of the vertebral arteries
smaller than anterior artery
connected across the midline
Segmental Spinal Arteries
supply vertebrae, intervertebral discs, contents of epidural space, and dura mater
come in a multiple levels
enter via intervertebral foramina
Cervical Branches Of Segmental Spinal Arteries
originate from vertebral arteries, thyrocervical trunk, and costocervical trunk
Thoracic Branches Of Segmental Spinal Arteries
come from posterior intercostal arteries
Lumbar Branches of Segmental Spinal Arteries
come from lumbar arteries
Artery of Adamkiewicz
only found on left side of body
is the greater anterior medullary artery
reinforces circulation to lumbar enlargement of spinal cord
anastomosis with anterior spinal artery
when two arteries join together
Veins Of Spinal Cord
drains to venous plexus on surface of spinal cord (located in subarachnoid space)
surface venous plexus joins intervertebral veins to external venous plexus
network of veins
External Venous Plexus
surrounds vertebral column
Batsons Veins
external and internal venous plexuses that connect the cranial cavity with venous plexus in pelvic cavity
no valves
how diseases spread from pelvis to cranium
Communicating Neuron
connects sensory and motor neurons
AKA interneuron
Sensory Neuron
Pseudobipolar neuron
Dorsal Nerve Root
only contains afferent neurons
Ventral Nerve Root
only contains efferent neurons
is a collection of nerve cell bodies in the peripheral nervous system
Peripheral Nervous System
outside spinal cord and brain
Each Ramus Has
motor and sensory branches
Motor Neurons Originate
in ventral horn of spinal cord axons
go out dorsal primary ramus
Sensory Neurons Originate
in dorsal root ganglion
go out through ventral primary ramus
also go into dorsal horn