Spinal Nerves

Question 1

Identify these features of a spinal nerve

Answer 1

Question 2

List what each pair of spinal nerves supplies to a dermatome

Answer 2

Somatic general sensory innervation

Motor functions

Reflex functions

Question 3

What is a dermatome?

Answer 3

An area of skin innervated by one spinal nerve

Question 4

Dorsal roots contain sensory axons only while ventral roots contain motor axons. True/false?

Answer 4

True

Question 5

The C5 dermatome covers which area of the arm?

Answer 5

Badge patch

Question 6

C6, C7 and C8 are the dermatomes of which fingers?

Answer 6

C6 - thumb

C7 - middle

C8 - little

Question 7

Where are the dermatomes for T1 and T2 located?

Answer 7

T1 - medial forearm

T2 - medial arm

Question 8

T4 is the dermatome that covers what part of the body?

Answer 8

Male nipple

Question 9

What dermatome is the umbilicus contained within?

Answer 9

T10

Question 10

Identify the dermatomes of the lower limb

Answer 10

Question 11

What is the difference between a spinal nerve and a named nerve?

Answer 11

A spinal nerve contains axons from one spinal cord level while a named nerve contains axons from one or more spinal cord level supplying a particular area

Question 12

What are the spinal nerve roots of the femoral nerve?

Answer 12

L2-L4

Question 13

Name the nerves supplying each part of the neck

Answer 13

Little

Goats

Tread

Softly

Question 14

Identify the named nerve cutaneous innervation of the upper limb

Answer 14

Question 15

Identify the named nerve cutaneous innervation of the anterior aspect of the lower limb

Answer 15

Question 16

Identify the named nerve cutaneous innervation of the posterior aspect of the lower limb

Answer 16

Question 17

Stimulating the area innervated by the femoral nerve causes an action potential in which part of the spinal cord?

Answer 17

Posterior horn

Question 18

Which two plexi are generally tested in myotome testing?

Answer 18

Brachial

Lumbosacral

Question 19

How can the C5 myotome be tested? Which muscle is mainly tested?

Answer 19

Shoulder abduction

Deltoid

Question 20

Which myotomes are tested in elbow flexion and extension?

Answer 20

C6 (flexion)

C7 (extension)

Question 21

A patient is unable to hold your finger in their clenched fingers when you pull it out. What myotome is affected?

Answer 21

C8

Question 22

What myotome is responsible for finger abduction?

Answer 22

T1

Question 23

The L3 myotome is responsible for what movement? What is the main muscle involved?

Answer 23

Knee extension

Quadriceps femoris

Question 24

What myotomes are responsible for ankle dorsiflexion and plantarflexion?

Answer 24

L4 (dorsiflexion)

L5 (plantarflexion)

Question 25

A patient is unable to stick their big toe in the air. Which myotome is affected?

Answer 25

L5

Question 26

What myotome is tested when asking a patient to flex their knee? What muscle enables this?

Answer 26

S2

Biceps femoris

Question 27

Outline what occurs in the patellar reflex

Answer 27

Quadriceps fibres are stretched causing APs in the anterior rami axons within the femoral nerve. These sensory APs are conducted to the posterior horn of L3 before synapsing on lower motor neurons that supply quadriceps

Question 28

What are the main spinal reflexes that can be tested? What are their nerve roots?

Answer 28

Biceps brachii (C5/6)

Brachioradialis (C6)

Triceps brachii (C7)

Knee jerk (L3)

Ankle jerk (S1)