lec 2

Question 1

the spinal cord ends opposite to in adult ? at birth? why?

Answer 1

the disc between L1 & 2 in adults. At birth, it ends opposite L3. Later, the vertebral column grows faster than the spinal cord.

Question 2

the spinal cord has 2 enlargement ?at which segment? they give origin to ?

Answer 2

1. Cervical enlargement: gives origin to brachial plexus (C4-T1).
2. Lumbar enlargement: gives origin to lumbar & sacral plexuses (L1-S4).

Question 3

the spinal cord consist of ——— segments which consist of ——–

Answer 3

31 segments →8 cervical, 12 thoracic, 5 lumbar, 5 sacral & 1 coccygeal

Question 4

C6 segment of spinal cord is opposite ———- vertebra (mention the rule )

Answer 4

C5

-1

Question 5

T6 segment of spinal cord is opposite —— vertebra (mention the rule)

Answer 5

-2 (upper 6 thoracic)

T4

Question 6

T12 segment of spinal cord is opposite —— vertebra (mention the rule)

Answer 6

-3 (lower 6 thoracic)

T9

Question 7

L5 segment of spinal cord is opposite —— vertebra (mention the rule)

Answer 7

-4 (lumber)

L1

Question 8

S2 segment of spinal cord is opposite —— vertebra (mention the rule)

Answer 8

All sacral & coccygeal segments →opposite L1-L2 vertebrae

Question 9

direction of roots of spinal cord
•C1&2 are
•C3-T12 are
•L1-Co are

Answer 9

horizontal
oblique
vertical

Question 10

Exit of spinal nerves from the vertebral canal

• C1-7
• T1-L5
• S1-4
• S5-Co

Answer 10

C1-7 pass above corresponding vertebrae.

• C8 passes below C7 vertebra.
• T1-L5 pass below corresponding vertebra. (C2-L5 exit via intervertebral foramina)
• S1-4 pass via the ant. & post. sacral foramina.
• S5 & Co pass via the sacral hiatus

Question 11

The collection of spinal nerves that surround the film terminale below the termination of the spinal cord (i.e., below L2) is called

Answer 11

cauda equina

Question 12

the largest spinal nerve is

Answer 12

1st sacral

Question 13

from above downwards what happens to the size of
spinal nerves
intervertebral foramina

Answer 13

increase

decrease

Question 14

The————- nerves are the most liable to compression

Answer 14

4th & 5th lumbar

Question 15

The 3 meningeal coverings of spinal cord (in ->out)

Answer 15

dura matter
arachnoid matter
pie matter

Question 16

the dura and arachnoid matter ends opposite

Answer 16

S2

Question 17

Pia mater is adherent to———& continuous below as the ————– which pierces—————- to be attached to——————

Answer 17

the cord
filum terminale
the tube of dura & arachnoid
the back of coccyx

Question 18

in which space can we find the CSF in spinal cord

Answer 18

subarachnoid space

Question 19

Ligamentum denticulatum has ———– teeth connecting ————

Answer 19

21

pia matter with the arachnoid and dura

Question 20

subarachnoid septum extends from ——– to ——–

Answer 20

posterior median septum –> arachnoid matter

Question 21

A needle is introduced to the spinal ————– Just above or just below the —————– which lies opposite ————–

Answer 21

subarachnoid space
tip of 4th lumbar spine
imaginary line connecting the highest points of iliac crests

Question 22

uses of lumber puncture

Answer 22

1. Diagnostic: to measure CSF pressure, obtain sample for analysis (meningitis), or inject air for contrast X-ray (air encephalography).
2. Therapeutic:to remove some CSF to relieve increased intracranial tension, or to inject antibiotics or spinal anesthesia

Question 23

grey matter parts

Answer 23

1. Anterior horn [motor]
2. Posterior horn [sensory]
3. ±Lateral horn [autonomic]

Question 24

grey matter structure

Answer 24

1. Nerve cells (nuclei).
2. Unmyelinated nerve fibers.
3. Neuroglia.
4. Capillaries.

Question 25

white matter structures

Answer 25

1. Myelinated nerve fibers (tracts). 2. Neuroglia. 3. Capillaries.

Question 26

Anterior root of spine contains

Answer 26

i. Motor fibers (from the anterior horn) | ii. ±Autonomic fibers (from the lateral horn).

Question 27

what type of neurons is the posterior root ganglion

Answer 27

pseudounipolar neurons

Question 28

the mixed nerve from the spine exits through the vertebral canal through

Answer 28

intervertebral foramen (IVF)

Question 29

which is larger the anterior or posterior ramus

Answer 29

anterior ramus

Question 30

Posterior ramus supplies

Answer 30

muscles & skin of the back

Question 31

All anterior rami form plexuses except the -----------

Answer 31

12 thoracic (intercostal nerves).

Question 32

Only ----------- rami send white rami communicants [preganglionic] to sympathetic ganglia

Answer 32

14 anterior (12 thoracic + upper 2 lumbar)

Question 33

All 31 anterior rami receive

Answer 33

grey rami communicants [postganglionic] from sympathetic ganglia

Question 34

Both rami of C1 spinal nerve are purely ---------

Answer 34

motor

Question 35

Recurrent meningeal nerve re-enters the spinal canal via IVF to supply the ? plays a role in ?

Answer 35

dura, periosteum, blood vessels & I.V. discs | It plays a role in referred pain or occipital headache

Question 36

mention each nucleus (site and function) in the dorsal horn

Answer 36

1. Substantia Gelatinosa of Rolandi: Present at tip of dorsal horn in all segments of spinal cord. * Function: pain modulation. 2. Nucleus Proprius(Main sensory nucleus): Present anterior to Substantia Gelatinosa in all segments of spinal cord. * Function: relays exteroception. 3. Nucleus Dorsalis “Clarke‟s Nucleus”: Present at the base of dorsal horn in C8 to L3 segments of the spinal cord. * Function: relays unconscious proprioception. 4. Visceral Afferent Nucleus: Present in C8 to L3 segments of the spinal cord lies lateral to Clarke‟s Nucleus. * Function: relays visceral sensations.

Question 37

group of autonomic neurons “Sacral Parasympathetic” is present in ------------

Answer 37

S2-3-4

Question 38

alpha motor neurons vs. gamma motor neurons

Answer 38

both pass in ventral root to supply muscle fibers alpha -> large gamma-> small , intrafusal muscle fibers

Question 39

The nuclei in the ventral horn are arranged in three groups (mention their location and what they supply ?

Answer 39

1. Medial Group: present throughout the whole length of the spinal cord and supply trunk muscles. 2. Central Group: present only in some cervical segments e.g. Phrenic Nucleus C3,4,5 & spinal accessory nucleus (C1-5). 3. Lateral Group: present in cervical & lumbosacral segments and supply limb muscles.

Question 40

mention each laminae of grey matter and its contents

Answer 40

* L I →marginal layer of Waldeyer. * L II + part of LIII →Substantia gelatinosa of Rolandi. * The rest of LIII + L IV →Main sensory nucleus. * Lamina VII →occupies the lateral horn & extends into the middle part of the anterior horn. * It contains: 1. Clarke's nucleus. 2. Lateral horn nuclei (intermediolateral & internediomedial). 3. Middle part of anterior horn (between L VIII & IX), contains Renshaw cells. * Laminae VIII-IX → occupy the anterior horn. L IX is lateral. It contains the motor neurons. LVIII is medial. It controls the muscle tone. * Lamina X → surrounds the central canal.