Peripheral nerves

Question 1

Myotomes and nerves for the following actions:
Shoulder abduction
Elbow flex
Elbow ext
Wrist flex
Wrist ext
Finger flex 
Finger ext
Finger abduction
Finger adduction

Answer 1

Shoulder abduction - C5, axillary
Elbow flex - C5-6, musculocutaneous nerve
Elbow ext - C6-7, radial
Wrist flex - C7-8, Median
Wrist ext - C6-7, radial
Finger flex - C8, median
Finger ext - C8, radial
Finger abduction -T1, ulnar
Finger adduction - T1, ulnar

Question 2

Shoulder abduction weakness, which nerve affected?

Answer 2

Axillary

Question 3

Shoulder adduction and elbow flexion. Which nerve affected?

Answer 3

C5

Question 4

Elbow, wrist and finger extension weakness. Nerve?

Answer 4

Radial

Question 5

Finger abduction and adduction. Nerve?

Answer 5

Ulnar and T1

Question 6

Nerves supply for following reflexes:
Biceps
Supinator
Tricep

Answer 6

Biceps C5-6
Supinator C5-6
Tricep C7

Question 7

Brachial plexus. Nerve supply for superior, middle and inferior trunk?

Answer 7

superior - C5/6 + suprascapular nerve
middle - C7
inferior - C8-T1

Question 8

Brachial plexus lesions. What are the motor and sensory deficits for the following:
Complete
Upper trunk/Erb’s/C5-6
Lower trunk/Klumpe/C8-T1

Answer 8

Complete
Motor: LMN weakness affecting the whole limb
Sensory - sensory loss of the whole limb
Other: Horner’s

Upper trunk/Erb’s/C5-6
Motor: Loss of shoulder movement and elbow flexion (waiter’s tip position)
Sensory: Loss over lateral aspect of the arm and forearm

Lower trunk/Klumpe/C8-T1
Motor: True clawhand with paralysis of intrinsic muscles
Sensory: Loss along medial aspect if hand and forearm
Other: Horner’s
Cervical rib: same as lower trunk but changes in pulse as well

Question 9

Brachial Plexus cords. What are the 3 cords?

Answer 9

Medial cord
- Ulnar + Median hand (abductor Pollicis Brevis) + Medial Antebrachial cutaneous nerve
Posterior cord
- Radial + axillary
Lateral cord
- musculocutaenous + pronator teres + pectoralis Major

Question 10

Myotomes and nerves for following actions:
Hip flexion
Hip extension
Knee flex
Knee ext
Plantar flex
Dorsiflex
Ankle eversion
Ankle inversion

Answer 10

Hip flexion - L2-3, Femoral
Hip extension - L4-5, Inferior gluteal
Knee flex - L3-4, Sciatic
Knee ext - L5-S1, femoral
Dorsiflex - L4-5, peroneal
Plantar flex- S1-S2, Tibial
Ankle eversion - L4
Ankle inversion - L5, S1

Question 11

Sciatic nerve:
Nerves
Motor 
Sensory
Other functions

Answer 11

Nerves:
L4,5,S1,S2

Motor:
Knee flexion (hamstring wekaness)
Loss of power of all muscles below the knee causing foot drop
Unable to stand on heels or toes

Sensory:
Sensation below knee

Other functions:
Loss of ankle jerk and plantar response
Knee jerk intact

Question 12

Tibial nerve:
Motor
Sensory

Answer 12

Posterior aspect of sciatic
Posterior compartment of leg

Motor:
Plantar flexion and foot eversion

Sensory:
Majority of sole of foot

Question 13

Femoral nerve:
Nerves
Motor
Sensation
Other functions

Answer 13

Nerves
L2,3,4

Motor
Weakness of knee extension (quadriceps paralysis)
Slight hip flexion weakness
Preserved adductor strength

Sensation:
Loss of inner aspect of thigh

Other functions:
Loss of knee jerk

Question 14

Common Peroneal nerve:
Nerves
Motor
Sensation

Answer 14

L4, 5, S1
Motor:
Dorsiflexion (deep peroneal)
Eversion of foot (superficial perioneal)
leads to foot drop

Sensation:
Lateral aspect of leg and dorsum of foot - superficial peroneal
Minimal over dorsum of foot - deep peroneal

Question 15

Straighten the leg:
Hip flexion->knee extension->plantar flexion -> inversion
L2/3 -> L3/4 -> L4/5 -> L5/S1
Femoral -> femoral -> tibial -> tibial

Answer 15

Hip flexion->knee extension->plantar flexion -> inversion
L2/3 -> L3/4 -> L4/5 -> L5/S1
Femoral -> femoral -> tibial -> tibial

Question 16

Bend everything:
Hip extension -> knee flexion -> dorsiflexion -> eversion
L4/5 -> L5/S1 -> S1/2 -> L4
Inferior gluteal -> sciatic -> deep peroneal -> superficial peroneal

Answer 16

Bend everything:
Hip extension -> knee flexion -> dorsiflexion -> eversion
L4/5 -> L5/S1 -> S1/2 -> L4
Inferior gluteal -> sciatic -> deep peroneal -> superficial peroneal

Question 17

List the 3 areas of nerve lesions for a foot drop and distinguishing factors.

Answer 17

L4/5

• eversion and inversion absent
• ankle jerk present

Sciatic
- eversion, inversion and ankle jerk absent

Common peroneal

• eversion absent
• inversion and ankle jerk present

Question 18

NCS. Define:
Amplitude
Latency and conduction velocity

Corresponding pathology?

Answer 18

Amplitude: response of how many axons were excited e.g. more people screaming, louder the sound
Loss represents axonal loss

Latency and conduction velocity:
The time between the onset of stimulus and peak of recording
Decrease in latency of conduction velocity = demyelination
f-wave latency

Question 19

What are the benefits of EMG?

Answer 19

Determine if there is a:
myopathic picture
Active or chronic neurogenic process
Single nerve fibre: neuromuscular junction
Change can occur early

Question 20

Charcot Marie tooth is a Hereditary peripheral neuropathy.
Genetic defect
Types
Presentation

Answer 20

Group of hereditary genetic neuropathies in which the peripheral neuropathy is either the sole or major component of the clinical syndrome.
Point mutations or copy number variations in genes coding for proteins with strategic functions.
AD

2 major groups:
CMT1 - demyelinating
CMT2 - axonal

Classic presentation:
Gradual distant weakness and senosry loss appearing within the 1st 2 decades of life
reduced deep tendon reflexes
skeletal deformities of the foot - pes cavus and hammertoes
Fine moevments of the hands for activities such as turning ket or using buttons and zippers may be impiared
Hands rarely affected as the feet
Pt remain ambulatory

Question 21

Hereditary Neuropathy with liability to pressure palsy (HNPP).
genetic defect
inheritance
presentation

Answer 21

Deletion of segment of chromosome 17p11.2 containing the PMP22 gene
AD

Presentation:
Transient and recurrent motor and sensory mononeurpaothies, typically occurring at entrapment sites such as carpel tunnel, ulnar groove and fibular head
Palsies may last for hours, days, weeks or occasionally longer.