Intervertebral Foramen: Regional Characteristics

Question 1

What are the average dimensions of the cervical intervertebral foramen?

Answer 1

about 10mm high and 5mm anterior to posterior

Question 2

What is the relationship of cervical intervertebral foramen height to nerve root size?

Answer 2

the height increases but the nerve root size stays about the same from cranial to caudal

Question 3

What parts of the cervical vertebra will modify the intervertebral foramen?

Answer 3

the lateral groove and uncinate process

Question 4

What increases the depth or length of the intervertebral foramen in the cervical spine?

Answer 4

TVP

Question 5

What is the location of the spinal nerve within the cervical intervertebral foramen?

Answer 5

toward the front and middle of the height of the cervical intervertebral foramen

Question 6

What happens to cervical nerve roots between their origin from the spinal cord and exit from the intervertebral foramen?

Answer 6

they descend along the spinal cord

Question 7

What is the relationship between aging and cervical spine nerve root characteristics?

Answer 7

the length of the nerve root increases as it descends from its apparent origin on the spinal cord, but the cross-sectional area of the nerve root decreases

Question 8

What is the relationship between aging and cervical spine intervertebral foramen size?

Answer 8

the cross-sectional area diminishes after age 50

Question 9

What are the specific attachment sites for a cervical spinal nerve?

Answer 9

the sulcus for the ventral primary ramus on the costotransverse bar and the vertebral artery

Question 10

What is the average height of the thoracic intervertebral foramen?

Answer 10

about 13mm

Question 11

What contributes to the anterior boundary of the thoracic intervertebral foramen?

Answer 11

the costocentral joint

Question 12

What is the average height of the lumbar intervertebral foramen?

Answer 12

about 17mm

Question 13

What is the amount of contribution of the intervertebral disc to the height of the lumbar intervertebral foramen?

Answer 13

about half

Question 14

What is the shape of the lumbar intervertebral foramen?

Answer 14

reniform or earlobe-shaped

Question 15

What is the relationship of lumbar nerve root size to intervertebral foramen size above L4?

Answer 15

the nerve root size will account for less than 22% of the available space

Question 16

What is the relationship of lumbar nerve root size to intervertebral foramen size below L4?

Answer 16

the nerve root size will account for up to 30% of the available space

Question 17

Which are the largest spinal nerves?

Answer 17

L5 and S1

Question 18

What increases the length of the intervertebral foramen at L5?

Answer 18

the lumbosacral tunnel

Question 19

What forms the lumbosacral tunnel?

Answer 19

• lumbosacral lig.
• TVP of L5
• sacral ala

Question 20

What condition is the result of encroachment on the L5 spinal nerve?

Answer 20

far out syndrome

Question 21

What lig. may contribute to the loss of size in the lumbar intervertebral foramen?

Answer 21

transforaminal lig.

Question 22

What is the relationship between intervertebral disc herniation and lumbar spine nerves?

Answer 22

the intervertebral disc above the intervertebral foramen is usually the source of damage

Question 23

What is unusual about the sacral intervertebral foramen compared to other intervertebral foramina?

Answer 23

a completely osseous boundary exists

Question 24

What is more likely the cause of nerve irritation at the sacral intervertebral foramen?

Answer 24

the tilt or position of the entire sacrum relative to the pelvis

Question 25

What is unique about the relationship of spinal nerve to intervertebral foramen at S5-Co1?

Answer 25

there are two nerves present, S5 nerve and Co1 nerve