Peripheral nerves Flashcards
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
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
Shoulder abduction weakness, which nerve affected?
Axillary
Shoulder adduction and elbow flexion. Which nerve affected?
C5
Elbow, wrist and finger extension weakness. Nerve?
Radial
Finger abduction and adduction. Nerve?
Ulnar and T1
Nerves supply for following reflexes:
Biceps
Supinator
Tricep
Biceps C5-6
Supinator C5-6
Tricep C7
Brachial plexus. Nerve supply for superior, middle and inferior trunk?
superior - C5/6 + suprascapular nerve
middle - C7
inferior - C8-T1
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
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
Brachial Plexus cords. What are the 3 cords?
Medial cord
- Ulnar + Median hand (abductor Pollicis Brevis) + Medial Antebrachial cutaneous nerve
Posterior cord
- Radial + axillary
Lateral cord
- musculocutaenous + pronator teres + pectoralis Major
Myotomes and nerves for following actions: Hip flexion Hip extension Knee flex Knee ext Plantar flex Dorsiflex Ankle eversion Ankle inversion
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
Sciatic nerve: Nerves Motor Sensory Other functions
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
Tibial nerve:
Motor
Sensory
Posterior aspect of sciatic
Posterior compartment of leg
Motor:
Plantar flexion and foot eversion
Sensory:
Majority of sole of foot
Femoral nerve: Nerves Motor Sensation Other functions
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
Common Peroneal nerve:
Nerves
Motor
Sensation
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
Straighten the leg:
Hip flexion->knee extension->plantar flexion -> inversion
L2/3 -> L3/4 -> L4/5 -> L5/S1
Femoral -> femoral -> tibial -> tibial
Hip flexion->knee extension->plantar flexion -> inversion
L2/3 -> L3/4 -> L4/5 -> L5/S1
Femoral -> femoral -> tibial -> tibial
Bend everything:
Hip extension -> knee flexion -> dorsiflexion -> eversion
L4/5 -> L5/S1 -> S1/2 -> L4
Inferior gluteal -> sciatic -> deep peroneal -> superficial peroneal
Bend everything:
Hip extension -> knee flexion -> dorsiflexion -> eversion
L4/5 -> L5/S1 -> S1/2 -> L4
Inferior gluteal -> sciatic -> deep peroneal -> superficial peroneal
List the 3 areas of nerve lesions for a foot drop and distinguishing factors.
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
NCS. Define:
Amplitude
Latency and conduction velocity
Corresponding pathology?
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
What are the benefits of EMG?
Determine if there is a: myopathic picture Active or chronic neurogenic process Single nerve fibre: neuromuscular junction Change can occur early
Charcot Marie tooth is a Hereditary peripheral neuropathy.
Genetic defect
Types
Presentation
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
Hereditary Neuropathy with liability to pressure palsy (HNPP).
genetic defect
inheritance
presentation
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.
