Spinal Cord Flashcards
Major reflex center and conduction pathway between the body and the brain
Spinal cord
Describe the shape of the spinal cord
Cylindrical, slightly flattened anteriorly and posteriorly
The spinal cord begins as a continuation of the
Medulla oblongata
This is the caudal part of the brain stem
Medulla
Length of spinal cord in adults
Extends from -
42-45 cm long
Foramen magnum in the occipital bone to the L1 or L2 vertebra
Tapering inferior end of spinal cord
Conus medullaris
Conus medullaris may terminate as high as — and as low as —
T12 vertebra
L3 vetebra
Spinal cord occupies what fraction of the vertebral canal
Superior 2/3
Number of nerves of the cervical segment
8
Number of nerves of thoracic level
12
Number of nerves of:
Lumbar
Sacral
Coccygeal
5
5
1
Nerve C1 passes superior or inferior to vertebra C1
Superior
True or False: Cervical spinal nerves bear the same aloha-numeric designation as the vertebrae forming the superior margin of the IV foramina
False - inferior IV foramina
Spinal nerves T1 to Co1 bear the same alphanumeric designation as the vertebrae forming the SUPERIOR or INFERIOR margin of their exit?
Superior
True or False: The first cervical nerves lack posterior roots in 70% of people and their coccygeal nerve may be absent.
False - 50%
True or False: In embryos, the spinal cord only occupies 1/3 of the whole length of the vertebral canal
False - whole length
True or False: In embryos, the cord segments lie approximately at the vertebral level of the lower number.
False - same number
Thus, spinal nerves passing laterally to exit the corresponding IV foramen
During the end of what embryonic week does the tail-like caudal eminence disappear and the number of coccygeal vertebrae is reduced?
8th week
By the end of embryonic period, coccygeal vertebrae is reduced from — to — segments.
6 to 4
Does the spinal cord in the vertebral canal of the coccyx atrophy?
Yes. By the end of 8th week
True or False:
During the fetal period, the spinal cord grows faster than the vertebral column.
False. The vertebral column grows faster than the spinal cord; thus, the cord ascends relative to the vertebral canal.
At birth, the tip of conus medullaris is at what vertebral level?
L4-L5 level
True or False:
In postnatal life, the vertebral column is shorter than the spinal cord
False. The spinal cord is shorter than the vertebral column;thus, there is obliquity of spinal nerve roots
The length of the nerve roots decreased progressively. True or False?
False. Because the distance between the origin of a nerve’s roots from the spinal cord and the nerve’s exit from the vertebral canal increases as the inferior of the vertebral column is approached, the length of the nerve roots also increases progressively.