Nerve Supply of the Back

Question 1

functions of spinal cord

Answer 1

relay center for incoming sensory info through dorsal roots & horn
conduit for ascending (afferent) and descending (efferent) pathways
origin of LMNs = commands to muscles of body from ventral horn

Question 2

What are meninges?

Answer 2

connective tissue membrane

Question 3

Name the meninges from inside out

Answer 3

pia, arachnoid, dura

Question 4

Subarachnoid space is filled with…

Answer 4

cerebrospinal fluid and arteries

Question 5

Subdural space is the location of:

Answer 5

veins

Question 6

The epidural space contains:

Answer 6

fat

Question 7

Describe Bell-Magendie Law

Answer 7

Sensory info goes into the spinal cord via dorsal (posterior) roots of spinal nerves
Motor “commands” leave the spinal cord via ventral (anterior) roots of spinal nerves

Question 8

Ventral horn contains:

Answer 8

cell bodies of alpha & gamma motor neurons (LMN)

Question 9

Dorsal horn contains:

Answer 9

sensory cell bodies

Question 10

How are spinal nerves numbered?

Answer 10

numbered for vertebrae above, except in cervical region
(i.e., C2= between C1-C2; C8 between C7-T1; T1 between T1-T2)

Question 11

Describe the dorsal root

Answer 11

Sensory (afferent) route
Formed by union of smaller dorsal rootlets which emerge from dorsal side of spinal cord
Larger than ventral root
*located inside vertebral canal

Question 12

what type of neuron is the dorsal root ganglion part of?

Answer 12

pseudounipolar

Question 13

what does each ramus carry?

Answer 13

mixed motor and sensory fibers from both ventral and dorsal horns

Question 14

spinal nerves are formed by union of…

Answer 14

dorsal and ventral roots in intervertebral foramen

Question 15

Describe the ventral root

Answer 15

Motor (efferent) route
Formed by union of smaller ventral rootlets from ventral side of spinal cord
*located inside vertebral canal

Question 16

Dorsal rami is divided into…

Answer 16

medial and lateral branches

Question 17

Dorsal rami motor innervation

Answer 17

intrinsic muscles of the back

Question 18

Medial branch of dorsal ramus function

Answer 18

all levels supply muscles, only levels T6 and up are also cutaneous (sensory to skin) to upper back

Question 19

Lateral branch of dorsal ramus function

Answer 19

all levels supply muscles, only levels T6 and below are also cutaneous to lower back and medial gluteus region

Question 20

Dorsal ramus of C1 name and function

Answer 20

suboccipital nerve
- does not branch
- supplies the muscles of the suboccipital triangle
- larger than ventral ramus

Question 21

Dorsal ramus of C2 medial branch function

Answer 21

greater occipital nerve
- cutaneous to back of scalp
- muscular

Question 22

Dorsal ramus of C2 lateral branch function

Answer 22

Motor

Question 23

Dorsal ramus of C3 medial branch function

Answer 23

third occipital nerve
- cutaneous at base of occipital
- muscular

Question 24

Dorsal ramus of C3 lateral branch function

Answer 24

muscular

Question 25

Dorsal ramus of C4-C5 medial branch function

Answer 25

cutaneous and muscular

Question 26

Dorsal ramus of C6-C8 medial branch function

Answer 26

muscular

Question 27

Dorsal ramus of C6-C8 lateral branch function

Answer 27

muscular

Question 28

Which dorsal rami do not split into medial and lateral branches?

Answer 28

C1, S4, S5, Cx1

Question 29

Dorsal ramus T1-T6 medial branch function

Answer 29

Cutaneous and muscular

Question 30

Dorsal ramus T1-T6 lateral branch function

Answer 30

Muscular

Question 31

Dorsal ramus T7-T12 medial branch function

Answer 31

Muscular

Question 32

Dorsal ramus T7-T12 lateral branch function

Answer 32

Cutaneous and muscular

Question 33

Dorsal ramus L1-L5 medial branch function

Answer 33

Muscular

Question 34

Dorsal ramus L1-L5 lateral branch function

Answer 34

Cutaneous and muscular

Question 35

Dorsal ramus S1-S3 medial branch function

Answer 35

Muscular

Question 36

Dorsal ramus S1-S3 lateral branch function

Answer 36

Cutaneous and muscular

Question 37

Dorsal ramus S4-S5 function

Answer 37

Cutaneous and muscular Does not divide

Question 38

Dorsal ramus Cx1 function

Answer 38

Cutaneous and muscular Does not divide

Question 39

Ventral rami motor innervation

Answer 39

Hypaxial muscles including limbs

Question 40

Ventral rami cutaneous innervation

Answer 40

Most of body except head and back

Question 41

Dorsal columns of white matter are:

Answer 41

Fasciculus gracilis, fasciculus cuneatus

Question 42

Dorsal columns of white matter function

Answer 42

Sensory information

Question 43

Ventral and lateral columns of white matter function

Answer 43

Several functions (mostly motor)

Question 44

Ventral rami: cervical plexus location and innervation

Answer 44

C2-C4 Innervates neck, parts of head and shoulders

Question 45

Ventral rami: brachial plexus location and innervation

Answer 45

C5-T1 innervates the pectoral girdle and upper limbs

Question 46

Ventral rami: lumbosacral plexus location and innervation

Answer 46

L1-S4 Innervates pelvic girdle and lower limbs

Question 47

what are dermatomes?

Answer 47

areas of skin innervated by cutaneous branches of a single spinal nerve

Question 48

What is the dermatome for C2 medial branch of dorsal ramus?

Answer 48

Greater occipital nerve dermatome: back of scalp