2: Peripheral Mononeuropathies Flashcards
What is carpal tunnel syndrome
Compression Median.N within carpal tunnel
What is the main risk factor for carpal tunnel syndrome
FH (Genetic)
What fractures predispose to median nerve injury
Distal radius
Lunate
What occupation predisposes to carpal tunnel syndrome
Jobs that involve repeated flexion and extension of the wrist
What 5 conditions predispose to carpal tunnel syndrome
OA RA Diabetes Pregnancy Hypothyroidism Oedema - HF
Where does median nerve arise
Lateral (C5-C7) and Median (C8-T1) trunk
What is a branch of the median nerve
Anterior interosseous nerve
What does damage to anterior interossus nerve cause
Loss of pronation of forearm and weakness of thumb and finger flexion
How do mild symptoms of carpal tunnel syndrome present
- Parasthesia over thumb, second finger and middle-finger which is worse at night
- Symptoms may be improved by patient putting arm over bed
How does severe carpal tunnel present
Weakness in pincer grip
What are 4 signs of carpal tunnel syndrome
- +ve Tinels
- +ve Phalens
- Weakness thumb abduction
- Thenar wasting
How may median nerve damage present
Pope blessing sign
What is pope blessing sign
Inability to flex first three digits
When does pope blessing sign occur
Damage to median nerve - not carpal tunnel syndrome
What is ordered in carpal tunnel syndrome
NCS
EMG
What is it called when ulna.N is compressed at the elbow
Cubital Tunnel Syndrome
What is it called when ulna.N is compressed at the wrist
Guyon Canal Syndrome
What can cause cubital tunnel syndrome
Trauma
Prolonged periods leaning on elbow
Tumour
What causes guyon canal syndrome
Cycling - rest on edge of hand
Hook of hamate fracture
What are motor signs of ulna nerve entrapment
Ulna Claw
Fromnent
Waterburg sign
What is claw hand deformity
Extension at MCP and Flexion at PIP
What is waternberg sign and what is it caused by
Permanent abduction little finger due to weak third interoessi
What is froment sign
When pinching a piece of paper there is flexion at IP joint to compensate for weakness in adductor policies brevis
What sensory loss occurs in ulna.N palsy
Hypothenar eminence
What will be seen in cubital tunnel syndrome
Pain referred to fore-arm
Where does the ulna nerve arise from
Medial cord (C8-T1)
What is the ulna paradox
Close to the paw the worse the claw
Explain ulna paradox
Ulna nerve innervates medial half of the flexor digitorum profundus. If ulna nerve is damaged higher up this looses innervation and reduces flexion at the PIP = meaning hand only appears with extension at MCP
What is used to investigate ulna nerve palsy
NCS
EMG
What are two causes of radial nerve palsy
saturday night palsy
humerus fracture
What is Saturday night palsy
draping arm over furniture for prolonged periods of time
What causes saturday night palsy
Intoxication
Anesthesia
why may a fractured humerus cause damage to radial nerve
As radial nerve runs in spiral groove
where does the radial nerve arise from
Posterior cord (C5-T1)
what is the main clinical feature of radial nerve palsy
Wrist drop
what are symptoms of radial nerve palsy
- Loss extension fingers and hand
- Loss extension at the wrist
where may sensory loss occur in radial nerve palsy
Anatomical snuffbox
if damaged in the arm what does radial nerve palsy cause
loss elbow extension
if damaged the fore-arm what does radial nerve palsy cause
weak supination
what is Erbs palsy
damage to upper brachial plexus
what nerve roots are damaged in erbs palsy
C5-C6
what are 3 causes of erbs palsy
- Excessive lateral traction when delivering shoulder dystocia
- Excessive lateral neck flexion
- Trauma: fall on head
what position will the arm be in in Erbs Palsy
Extended and internally rotated = waiter’s tip
what is waiter’s tip position
Extended and internally rotated
what is a sign of erbs palsy in infants
Asymmetrical morro reflex
what does loss of innervation to biceps and brachioradialis cause in erbs palsy
Loss supination and flexion
what does impaired innervation to infraspinatus in Erbs palsy cause
Impaired external rotation
what does impaired innervation to deltoid cause in erbs palsy
Impaired abduction
what is used to manage erbs palsy
Bracing - external rotation and flexion
what is Klumpke’s paralysis
damage to lower brachial plexus
what nerve roots are affected in klumpke’s palsy
C8-T1
what are the two causes of klumpke’s paralysis
- Excessive abduction
- Pancoast tumour
- Cervical rib
what may cause hyperabduction of the arm
Holding onto branch when hanging from a tree
what may cause compression leading to klumphes paralysis
Pancoast tumour
Cervical rib
what is lost in Klumpke paralysis
Intrinsic muscles of the hand movement
what is foot drop
weakness in dorsiflexors of the foot
what can cause foot drop
- common perineal nerve injury
- sciatic nerve injury
- L5 radiculopathy
what causes common perineal nerve injury
- Fibular head fracture
- Compression = sitting cross-legged, cast
what gait does foot drop lead to
High-stepping
what movements are weak in common perineal nerve lesion
Dorsiflexion
Eversion
where is sensation lost in common perineal nerve injury
Dorsum of the foot and between first and second toe
what roots does common perineal nerve originate
L4-S2
what can cause axillary nerve palsy
- Fracture at surgical neck of humerus
- Anterior shoulder dislocation
how does axillary nerve palsy present
Impaired abduction and external rotation of the arm
where does axillary nerve arise
C5-C6
what does damage do musculcutaneous nerve cause
Loss flexion and supination
where does musculocutaneous nerve arise
C5-C7
what can damage long-thoracic nerve
Lymph node clearance in mastectomy
what does long thoracic nerve damage cause
Winged scapula
how will phrenic nerve damage present
Elevation diaphragm on that side
what nerve compression causes anaesthesia over lateral aspect of the thigh
lateral femoral cutaneous nerve
what can cause lateral femoral cutaneous nerve palsy
compression under ilioinguinal ligament due to increase in intra-abdominal pressure (pregnancy, tumour)
external compression (belts, pants)
local compression (tumour)
what nerve can be damaged in lymph node biopsy from posterior triangle of the neck
axillary nerve
what nerve can be damaged in thyroidectomy
recurrent laryngeal nerve
what nerve can be damaged when using Lloyd Davies stirrups
common perineal nerve
what nerve can be damaged in inguinal hernia repair
ilioinguinal nerve
