Spinal Canal & Spinal Cord Relationships

Question 1

at the intervertebral foramen, what is the relationship between spinal nerve number and vertebral number

Answer 1

in the cervical spine, spinal nerves exit above the segment they are numbered after (C8 nerve is the exception to this rule)
in the thoracic spine, lumbar spine, and sacrum, spinal nerves exit below the segment they are numbered after (Co1 nerve is the exception to this rule
C3 nerve exits about C3 or between C2/C3; T6 nerve exits below T6 or between T6/T7

Question 2

what is the relationship between rib number and verebral numbers at the costocentral joint

Answer 2

rib number always equates to same vertebral number at the costocentral joint: rib 3 articulates with T3 segment and also with the T2 segment. Only ribs 1, 11, and 12 typically joint with a single segment

Question 3

what is the relationship between spinal nerve umber, rib number and vertebral number in a thoracic intervertebral foramen

Answer 3

the spinal nerve number relates to the upper segment number in the vertebral couple. the rib number relates to the lower segment number in the vertebral couple. i.e. T3 nerve exits the intervertebral foramen formed by T3/T4, rib 4 joints with the same vertebral couple