ANATOMY OF THE SPINAL CORD Flashcards
The_______________ is a long cylindrical structure, covered by meninges, flattened anteroposteriorly & occupies most of the cranial 2/3rd of the vertebral canal.
spinal cord
The extent of the spinal cord from the medulla oblongata at the foramen magnum to terminate caudally (distally) as the ____________ in the adult at L1 level
conus medullaris
In a 3 month-old fetus, it extends the whole length of the vertebral canal at level of __ vertebra
S2
In a 3 month-old fetus, it extends the whole length of the vertebral canal at level of S2 vertebra, but because of greater growth in length of the vertebral column than in the spinal cord, the ___________ lies at the level of L2 vertebra at birth & at lower limit of L1 or upper limit of __ at the age of 20.
conus medullaris, L2
Beyond the conus medullaris, a prolongation of pia mater extends as a thin cord- ___________
Filum terminale
The Filum terminale is attached to the posterior aspect of the _st coccygeal segment.
1st coccygeal segment.
In adults, the spinal cord measures __ - __ cm long (from foramen magnum to level of L1/L2 vertebra).
42-45 cm
FUNCTIONS
- The spinal cord is the major _________ & ____________ between the body & the brain.
- The spinal cord carries messages between the CNS and the rest of the body, and mediates numerous spinal reflexes such as the _________
- reflex center & conduction pathway
2. knee-jerk reflex.
_______ ligaments are 2 flattened bands of pial tissue that attach to the spinal dura with about 21 teeth
Dentate ligaments
_________ is a pial filament extending from the conus medullaris to the end of the dural sac , with which it fuses
Filum terminale
_________ provide the strongest anchorage & fixation of the spinal cord to the vertebral canal
Spinal nerve roots
There are 31 pairs of spinal nerves which arise from each side of the spinal cord namely:
_ cervical
__ thoracic
_ lumbar
_ sacral
_ coccygeal
The spinal nerves contain both motor & sensory fibres
8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
The part of the spinal cord from which a pair of spinal nerves arises is called a _____ segment
spinal segment
Dorsal root contain _______ nerve fibers with a Dorsal root ganglion
Sensory
Ventral root contain ______ and Autonomic nerves fibers
Motor
The Dorsal & Ventral roots unite at the _________ foramen to form the spinal nerve
Next, Having left the vertebral canal,
spinal nerves divide into _____ & _____ rami, each of which carry motor & sensory nerves.
Intervertebral foramen,
Dorsal & Ventral rami,
- Spinal nerves C1 to C7 exit _____ the pedicle of the corresponding vertebrae
- ALL other spinal nerves exit _____ the pedicles of the corresponding vertebrae
- the C8 nerve passes _____ the pedicle of C7 (there is noC8 vertebra)
- L5 nerve passes under the pedicle of the L5 vertebra.
- above
- below
- under
- L5
The lumbar, sacral & coccygeal roots that exit below the conus at L1/L2 are contained within the dura as far as its lower limit at S2 & are called the ____________
Cauda Equina
The lumbar & sacral roots below the end (termination) of the cord at vertebral level L2, continue as a leash of nerve roots termed the _____________
Cauda equina