APE 3: The Peripheral Nervous System

Question 1

How many spinal nerve roots supply the upper limb?

Answer 1

5

Question 2

Which spinal nerve roots supply the upper limb?

Answer 2

C5-T1

Question 3

How many trunks does the brachial plexus have and what are they?

Answer 3

• three trunks

- superior, middle and inferior

Question 4

What do the trunks of the brachial plexus cross?

Answer 4

The posterior triangle of the neck

Question 5

How many divisions does the brachial plexus have and what are they?

Answer 5

• six divisions

- anterior and posterior parts of each trunk

Question 6

How many cords does the brachial plexus have and what are they?

Answer 6

• three cords

- lateral, posterior and medial

Question 7

Which nerves make up the 5 main branches of the brachial plexus?

Answer 7

• Musculocutaneous nerve
• Axillary nerve
• Median nerve
• Radial nerve
• Ulnar nerve

Question 8

Which muscles does the musculocutaneous nerve innervate?

Answer 8

Brachialis, biceps brachii and coracobrachialis

Question 9

What muscles does the axillary nerve innervate?

Answer 9

Teres minor and deltoid muscles

Question 10

What muscles does the median nerve innervate?

Answer 10

Most of flexor muscles in arm, thenar muscles, lateral palmar- first 3 and a half digits

Question 11

What muscles does the radial nerve innervate?

Answer 11

Triceps brachii and muscles in posterior compartment of forearm

Question 12

What muscles does the ulnar nerve innervate?

Answer 12

Muscles of the hand, flexor carpi ulnaris and medial half of flexor digitorum profundus

Question 13

Where is the axillary nerve most vulnerable to damage?

Answer 13

Within the axilla

Question 14

When might the axillary nerve be injured?

Answer 14

By direct trauma to the shoulder, fracture of the humeral surgical neck, shoulder dislocation

Question 15

What won’t the patient be able to do with a damaged axillary nerve?

Answer 15

Unable to abduct shoulders, shoulder becomes flattened in appearance

Question 16

Where is the radial nerve most vulnerable to damage?

Answer 16

In the radial groove

Question 17

What will cause damage to the radial nerve?

Answer 17

Fracture of the humeral shaft

Question 18

What will be seen in a patient with damage to the radial nerve?

Answer 18

Inability to extend wrist and fingers, causes wrist drop

Question 19

Where is the ulnar nerve most vulnerable to damage?

Answer 19

As it passes behind the medial epicondyle of the humerus

Question 20

What can cause damage to the ulnar nerve?

Answer 20

Trauma at the level of the medial epicondyle (at the elbow)

Question 21

What can be seen in a patient with damage to the ulnar nerve?

Answer 21

Flexion of the wrist is accompanied by abduction, abduction and adduction of the fingers and thumb can’t occur, movement of 4th and 5th digits is impaired

Question 22

Where is the median nerve most vulnerable to damage?

Answer 22

Deep to the flexor retinaculum in the wrist

Question 23

What can cause damage to the median nerve?

Answer 23

Lacerations just proximal to the flexor retinaculum, carpal tunnels syndrome

Question 24

What can be seen in a patient with damage to the median nerve

Answer 24

Paralysed thenar muscles and two lateral lumbricals

Question 25

How many spinal roots supply the lower limb?

Answer 25

8

Question 26

Which spinal nerve roots supply the lower limb?

Answer 26

L1-S3

Question 27

What spinal nerve roots supply just the lumbar plexus?

Answer 27

L1-L4

Question 28

What does the lumbar plexus branch within?

Answer 28

Psoas major muscle

Question 29

What is lateral and medial to the psoas major muscle

Answer 29

Lateral is the femoral nerve | Medial is the obturator nerve

Question 30

Which compartments of the thigh does the lumbar plexus supply?

Answer 30

Anterior and medial compartments

Question 31

What is the rest of the lower limb supplied by?

Answer 31

The sacral plexus

Question 32

Which spinal nerve roots supply the sacral plexus?

Answer 32

S1-S3 and the lumbosacral trunk (L4/L5)

Question 33

Where is the sciatic nerve found?

Answer 33

Inferior to the piriformis muscle and deep to the hamstring muscle

Question 34

How can the sciatic nerve be commonly injured?

Answer 34

Intramuscular injections

Question 35

Which compartment of the thigh does the sciatic nerve supply?

Answer 35

Posterior compartment

Question 36

Which two branches does the sciatic nerve bifurcate into

Answer 36

Tibial nerve and common fibular (peroneal) nerve

Question 37

What does the tibial branch of the sciatic nerve supply?

Answer 37

The posterior thigh (hamstrings) muscles

Question 38

Which other muscles does the tibial nerve supply?

Answer 38

Soleus and gastrocnemius

Question 39

Where does the common fibular nerve wrap around?

Answer 39

The neck of the fibula

Question 40

What causes damage to the common fibular nerve?

Answer 40

Fracture to the fibula or tight plaster cast

Question 41

What happens as a result of damage to the common fibular nerve?

Answer 41

Foot drop

Question 42

Which compartment of the thigh does the femoral nerve supply?

Answer 42

Anterior compartment of the thigh (quadriceps)

Question 43

What 2 actions is the quadriceps muscle responsible for?

Answer 43

Hip flexion and leg extension

Question 44

Which compartment of the thigh does the obturator nerve supply?

Answer 44

Medial compartment (adductor)

Question 45

What type of pathology can cause irritation to the medial compartment of the thigh?

Answer 45

Ovarian pathology

Question 46

How many roots attach a spinal nerve to the cord?

Answer 46

2

Question 47

What does the anterior (ventral) root contain?

Answer 47

Motor fibres leaving the spinal cord

Question 48

What does the posterior (dorsal) root contain?

Answer 48

Sensory fibres entering the spinal cord

Question 49

Which root contains a ganglion?

Answer 49

The dorsal root

Question 50

What does the dorsal root ganglia contain?

Answer 50

The cell bodies of primary sensory neurons

Question 51

How are the nerves numbers with respect to their vertebrae and what is the exception to this?

Answer 51

Number of vertebrae is the same as the number of nerves | Exception= cervical region where there’s 8 nerves but only 7 vertebrae

Question 52

How do nerves travel with respect to their vertebrae and what is the exception to this?

Answer 52

A nerve always travels inferiorly to its vertebrae Exception= in cervical vertebrae, 7 nerve are all superior to its vertebrae and the 8th nerve is inferior to the 7th vertebra

Question 53

What do the nerves divide into?

Answer 53

Anterior and posterior primary rami

Question 54

Where does the posterior rami pass to and what does it supply?

Answer 54

Passes dorsally to supply the extensor muscles of the spine and overlying skin

Question 55

Where does the anterior rami pass to and what does it supply?

Answer 55

Passes ventral to supply the limbs and the body wall

Question 56

Which common viral infection can affect the skin of an individual dermatome?

Answer 56

Shingles, herpes virus

Question 57

What are the intercostal nerves?

Answer 57

Spinal nerves emerging from the vertebral column and running with the ribs

Question 58

How many intercostal and subcostal nerves are there and where does the subcostal nerve run?

Answer 58

11 intercostal and 1 subcostal | The subcostal nerve runs under rib 12

Question 59

What are the two ‘beads on string’ that run on either side of the vertebral column?

Answer 59

The sympathetic chains

Question 60

What supplies the sympathetic chains?

Answer 60

The thoraco-lumbar regions of the spinal cord

Question 61

Which nerve innervates the thorax and the abdomen?

Answer 61

The vagus nerve

Question 62

Which nerve supplies the diaphragm and which vertebral level is it at?

Answer 62

The phrenic nerve- C3,4,5

Question 63

What is the phrenic nerve important for?

Answer 63

Breathing

Question 64

What innervates the limbs?

Answer 64

The cervical and lumbar enlargements

Question 65

What is the conus medullaris

Answer 65

Where the spinal cord ends at a tapering point

Question 66

What is the cauda equina composed of?

Answer 66

Many dull, yellow-coloured roots

Question 67

What is the filum terminale?

Answer 67

A single white fibrous cord

Question 68

At which vertebral level and anatomical landmark is lumbar puncture done?

Answer 68

L4, where there is the line connecting both iliac crests

Question 69

What is the denticulate ligament?

Answer 69

What the pia mater forms on either side of the spinal cord between the dorsal and ventral roots

Question 70

Where is the needle placed to perform an epidural?

Answer 70

Outside the dural sac