spinal cord

Question 1

describe the basic anatomy of the spineal cord

Answer 1

connects with brain, passes through foramen magnum, protected by vertebral canal
has 4 segments, 2 enlargements, connects bilaterally with spinal nerves
ends inferiorly at L1/L2 intervertebral disc level

Question 2

name the 4 segments and 2 enlargements of the spinal cord

Answer 2

4 segments = cervical, thoracic, lumbar, sacral/coccygeal

2 enlargements = cervical, lumbosacral

Question 3

how many spinal nerves are in each segment of the spinal cord

Answer 3

8 cervical (C1-C8)
12 thoracic (T1-T12)
5 lumbar (L1-L5)
5 sacral (S1-S5)
1 coccygeal (Co)

Question 4

how do vertebrae relate to the naming of spinal nerves

Answer 4

spinal nerves are named according to the vertebrae above them, except the cervical region which are named by the vertebrae below

Question 5

give the number of total vertebrae and how many vertebrae there are in each segment

Answer 5

33 in total 
cervical = 7
thoracic = 12 
lumbar = 5
sacral = 5(fused to form 1 sacrum)
coccygeal = 4(fused to form one coccyx)

Question 6

what are the 3 rules of spinal anatomy

Answer 6

spinal nerves supply the soma(body wall)
located only within the intervertebral foramina
from intervertebral foramina they connect with structures of the soma(via rami) and the spinal cord(via roots and rootlets)

Question 7

what’s the difference between rami and roots/rootlets

Answer 7

rami = always mixed modalities, different type of nerve fibre
roots/rootlets = one modality, on type of nerve fibre

Question 8

each pair of spinal nerves supplies one strip of soma(body wall), what strip do the anterior and posterior rami supply

Answer 8

posterior rami = supplies small posterior strip

anterior rami = supplies remainder of posterior strip, the lateral and anterior parts of the strip

Question 9

describe the pathway of a spinal nerve from gray matter to anterior rami

Answer 9

white matter is outside grey matter, rootlets come from grey matter, become slightly larger and become roots, then come together to form spinal nerve and splits into posterior(smaller) and anterior(larger) rami

Question 10

describe what is meant by segmental innervation and dermatomes

Answer 10

segmental innervation = body wall is divided into segments and each one is supplied by a single pair of nerves
dermatomes = area of skin supplied by both the anterior and posterior rami of a spinal nerve(except limbs-no posterior rami)

Question 11

describe what is meant by nerve plexuses and give the 4 examples

Answer 11

nerve plexuses = networks of intertwined anterior rami

cranial plexus, lumbar plexus, brachial plexus and sacral plexus