Spinal Cord

Question 1

Site

Answer 1

Upper 2/3 of the vertebral canal

Question 2

Length

Answer 2

45 cm in males and 42 in females

Question 3

Extent (above )

Answer 3

Above :as a continuation of the medulla ablongata at the lower border of foramen magnum at the level of 1st cervical nerve

Question 4

Extent (below )

Answer 4

Tapers forming the conus medullaris

Question 5

How does the length of the spinal cord changes as the age changes

Answer 5

1) by the 3rd month(iul):occupies the whole vertebral column
2) at birth : ite ends at the level of l3
3) in adult : at the level of the disc between l1/l2

Question 6

Why is the spinal cord shorter than the vertebral coloumn

Answer 6

Due to the differential growth between the spinal cord(slow) and the vertebral coloumn (fast)

Question 7

Shape

Answer 7

Cylindrical with with enlargements

• cervical
• lumbar

Question 8

Cervical enlargmenet

Answer 8

From c5 to T1 _________brachial plexus

Question 9

Lumbar enlargement

Answer 9

From L1 to S3 (lumbar and sacral plexuses)

Question 10

External features

Answer 10

6 sulci or grooves

Question 11

Fissures

Answer 11

Anterior median fisssure (deepest)

Question 12

Sulci

Answer 12

Posterior median sulcus
Two anterolateral sulci
Two posterolateral sulci

Question 13

Anterolateral sulci

Answer 13

Exit of motor roots

Question 14

Posterolateral sulci

Answer 14

Entery of sensory roots

Question 15

Number of spinal segments

Answer 15

31 , each segment gives origin to a pair (R & L)

8 cervical , 12 thoracic , 5 lumbar, 5 sacral , 1 coccygeal

Question 16

Attachement of spinal nerves

Answer 16

Attached by 2 roots (motor ) ventral

Sensory (dorsal)

Question 17

Types of sensation(sensory)

Answer 17

Somatic / visceral / special senses

General somatic afferent
General visceral afferent
Special es

Question 18

Types of motor sensation

Answer 18

Visceral / somatic / special visceral

Efferent

Question 19

Ventral root (motor)

Answer 19

Somatic efferent fibers

Question 20

Dorsal root

Answer 20

General somatic afferent fibers

Question 21

Dorsal root ganglion

Answer 21

Sensory and have no relay

Question 22

Spinal nerve trunk ( ramus)

Answer 22

Mixed

Question 23

Root

Answer 23

Pure

Question 24

Vertebral levels of spinal cord segments

Answer 24

Cervical --- +1 
Upper thoracic-----+2
Lower thoracic ------ +3 
T11 --------opposite to l1 to L5
T12 and L1 -------- opposite to all sacral segments

Question 25

Cauda equina

Answer 25

Lengthening of the roots of lumbar and sacral nerves which have have to descend downward to reach their exit foramina

Question 26

Spinal meninges

Answer 26

Pia, arachnoid, dura matter

Question 27

What is spinal pia matter

Answer 27

It is a delicate membrane which is closely adherent to the spinal cord

Question 28

Prolongations of spinal pia matter

Answer 28

Outwards ----- forming th sheath around spinal nerves I