Spinal Cord

Question 1

anterior and caudal extent of spinal cord

Answer 1

foramen magnum

level of the L1-L2 vertebra

Question 2

Approximate length of SC

Answer 2

Males 45 cm

Females 42 cm

Question 3

denticulate ligaments

Answer 3

pial folds that stretch from the surface of the cord to the dural sheath midway between the dorsal and ventral roots

serve as landmarks in identifying the anterolateral segments of the cord for cordotomies for relief of intractable pain

Question 4

31 segments of spinal cord

Answer 4

8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal

Question 5

position of spinal nerves in relation to the vertebrae

Answer 5

C1 above the atlas
C8 below the C7 vertebrae and above T1
all other spinal nerves exit beneath corresponding vertebrae

Question 6

Relationship of Spinal Cord Segments and vertebral spines

Answer 6

C1 SC - C1 spine
C7 SC - C6 spine
T6 SC - T4 spine
L1 SC - T10 spine
S1 SC - T12 to L1 spine

Question 7

Cellular Organization of the spinal cord
Lamina I
Lamina II
III, IV
V
VI
VII
VIII
IX
X

Answer 7

Lamina I - posteromarginal nucleus
Lamina II - substantia gelatinosa
III, IV - nucleus proprius
V - neck of posterior horn
VI - base of posterior horn
VII - intermediate zone, intermediolateral horn
VIII - commissural nucleus
IX - ventral horn
X - grisea centralis

Question 8

extends from the tip of the conus and attaches to coccygeal ligament made of pia

Answer 8

Filum terminale

Question 9

cervical enlargment

Answer 9

C5-T1

Question 10

lumbar enlargement

Answer 10

L2-S3

Question 11

True or False
Dorsal medial fissure: shallow
Ventral Medial Fissure: deep

Answer 11

True

Question 12

from PICA, supplies posetrior one-third of spinal cord

Answer 12

Posterior Spinal Arteries

Question 13

Largest radicular artery

arises from Left side at T10 in approximately 80% of people

Answer 13

Artery of Admakiewicz

Question 14

Primary watershed areas

Answer 14

Midthoracic region of the SPinal Cord, Levels T1-T4 and T8-T9 prone to ischemic change during thoracic surgery or hypotension

Question 15

Venous drainage

Answer 15

diffuse -> epidural -> empty into vena cava

Question 16

ependymomal tumor that presents at the lumbar cistern

Arises from a remnant of ependymal cells from the central canal

Answer 16

Myxopapillary ependymoma

Question 17

areas of SC where proportion of gray to white is greates

Answer 17

lumbar and cervical

Question 18

Gray Matter Lamina with
interneurons, respond to noxious stimuli, sensibility to pain, release naturally occurring opiates, thereby limiting release of substance P from pain sensitive dorsal root fiber

Answer 18

Lamina II

Substantia Gelatinosa

Question 19

Gray Matter Lamina
Neurons that receive inputs from large fiber , which mediate finely locali ed touch,
stereognosis, proprioception, vibration sense.
Secrete γ-aminobutyric acid (GABA).

Answer 19

Laminae III, IV, V, VI

Nucleus Proprius

Question 20

Gray Matter Lamina
From T1–L2, receives inputs on joint position and sends info to the cerebellum via the
dorsal spinocerebellar tract.

Answer 20

Lamina VII

Clarke’s Column

Question 21

Gray Matter Lamina

From T1–L2, preganglionic neurons project to sympathetic ganglia.

Answer 21

Lamina VII

Intermediolateral cell column

Question 22

Gray matter lamina
Involved in reflxes, main target of descending motor commands from motor/
premotor cortex and brain stem.
■ All inhibitory, use glycine > GABA.
■ 1a interneurons: Inhibit motor neurons of antagonist muscle; receive sensory input
from agonist muscle’s spindle afferents.
■ 1b interneurons: Inhibit motor neurons of agonist muscle; receive sensory input
from agonist muscle’s Golgi tendon organs.
■ Renshaw cells: Have direct input agonist muscle, inhibits agonist motor neuron and
the interneurons of antagonist muscles → increases antagonist muscle tone.

Answer 22

Lamina VIII

Ventral horn interneurons

Question 23

Gray Matter Lamina
Pools of motor neurons that innervate skeletal musculature.
■ α1: Innervate fatigable and fatigue-resistant fast-twitch muscles.
■ α-II: Innervate fatigue-resistant slow-twitch muscles.
■ γ: Innervate intrafusal muscle fibers of muscle spindle .

Answer 23

Lamina IX

Ventral horn motor neurons