Lower limb nerve injuries and compression syndromes Flashcards Preview

Module 204 Theme 2 > Lower limb nerve injuries and compression syndromes > Flashcards

Flashcards in Lower limb nerve injuries and compression syndromes Deck (84):
1

Where is the conus medularis?

L1/L2

2

What is found below the conus medularis?

Cauda equina

3

Where are lumbar punctures taken?

Below L3

4

Describe the severity of cauda equina pain

Radicular
More severe

5

Describe the severity of conus medularis pain

Less severe

6

Give the location of the cauda equine pain

Unilateral/asymmetric Perineum, thighs, and legs.

7

Give the location of conus medularis

Bilateral Perineum, thighs

8

Describe the sensory disturbance of the cauda equina

Saddle Unilateral/asymmetric

9

Describe the sensory disturbance of the conus medularis

Bilateral saddle distribution

10

Describe the motor loss of cauda equina

Asymmetric and atrophy

11

Describe the reflexes of cauda equina

Ankle and knee reduced

12

Describe the reflexes of conus medularis

Ankle only reduced

13

Describe the bowel and bladder in cauda equina

Late

14

Describe the bowel and bladder in conus medularis

Early

15

Describe sexual function in cauda equina

Impaired - less severe

16

Describe sexual function in conus medularis

Impaired - more severe

17

List some causes of cauda equina

Disc herniation

Spinal fracture

Tumour

18

List some causes of conus medularis

Disc herniation

Tumour

Inflammatory conditions

Infections

19

List some inflammatory conditions which may cause conus medularis

Chronic inflammatory demyelinating
Polyradiculopathy
Sarcoidosis

20

List some infections which may cause conus medularis

CMV
HSV
EBV
Lyme
TB

21

Describe sciatica

Compression- Disc- posterior central, lateral Bone- osteophyte Ligaments Small canal- stenosis

22

Which nerve roots is sciatica usually?

L5,S1

23

Where is the L5 nerve root?

Between L5 and S1 vertebral bodies

24

Where is the S1 nerve root?

Between S1 and S2 vertebral bodies

25

Where may pain be felt in sciatica?

Dermatome (sharp/superficial)

Myotome (deep ache)

26

What is the L1 dermatome?

Inguinal area

27

What is the L2 dermatome?

Front of thigh (front pocket)

28

What is the L3 dermatome?

Front of knee

29

What is the L4 dermatome?

Front-inner/medial leg

30

What is the L5 dermatome?

Outer leg, dorsum of the foot, inner sole

31

What is the S1 dermatome?

Little toe, rest of sole, back of leg

32

What is the S2 dermatome?

Thigh to top of buttock (back pocket)

33

Where are the S3-S5 dermatomes?

Rings around anus and genitalia

34

Which spinal level is the knee jerk reflex?

L4

35

Which spinal nerve is the ankle jerk reflex?

S1

36

Which action does L1/2 do?

Hip flexion

37

Which action does L3/4 do?

Knee extension

38

Which action does L4 do?

Foot inversion

39

What action does L5 do?

Knee flexion
Ankle dorsiflexion
Toe extension
Foot inversion and eversion

40

What action does S1 do?

Knee flexion
Ankle plantar flexion
Toe flexion
Foot eversion

41

List the causes of lumbosacral plexus lesions

Childbirth
Structural
Non structural

42

List some structural causes of lumbosacral plexus lesions

Haematoma (on Warfarin
Abscess
Malignancy – infiltration
Trauma

43

List some non-structural causes of lumbosacral plexus lesions

– Inflammatory
– Diabetes
– Vasculitis
– Radiotherapy

44

What would be affected in proximal femoral nerve damage?

Hip flexors, Iliopsoas

45

What would be affected of a lesion in the femoral nerve below the inguinal ligament

knee extension

46

How can the femoral nerve be damaged?

Surgery Gynae procedures, esp hysterectomy, femoral a. bypass/ puncture

47

What may be the cause of sciatica

Trauma
Haematoma Rarely sciatic nerve compression per se (Piriformis synd)
misplaced IM injection

48

Describe piriformis syndrome

Controversial as to whether muscle compression per se can cause tingling in buttock and down leg (eg after exercise or straining, or prolonged sitting)

Probably may rarely occur in those with anatomical predisposition.

No consensus on criteria Diagnosis of exclusion

49

What can partial sciatic nerve damage look like?

Common peronal or Tibial nerve damage

50

Where is the tibial nerve located?

Behind the knee

51

What actions cant be performed after tibial nerve damage?

Can’t stand on tiptoes
Weak foot inversion
Painful numb sole

52

List some causes of tibial nerve damage

Trauma: Haemorrhage
Bakers cyst
Nerve tumour
Entrapment by the tendinous arch at the soleus muscle.

53

Where does the tibial nerve branch?

Popliteal fossa

54

Name the branches of the tibial nerve

gastrocnemius, popliteus, soleus and plantaris, and the sural nerve.

55

What passes through the tarsal tunnel?

tibialis posterior, flexor digitorum longus, flexor hallucis longus

Intrinsic foot muscles

56

Give some symptoms of tarsal tunnel syndrome

Sole pain worse standing/ walking
Not heel pain

57

What would be a differential for tarsal tunnel?

Differential Morton’s neuroma

58

How may the common peronal nerve be damaged?

May also be damaged by tight plaster casts, leg crossing, Weight loss- slimmers palsy

59

Give the sensory loss of damage to the common peronal nerve

dorsum of foot and outer aspect lower leg

60

What weakness would result from damage to the common peronal nerve?

dorsiflexion and eversion of foot

61

List the nerves which could be affected in neurogenic foot dropo

Upper motor neuron (brain/ spinal cord) 
Conus 
L4/L5 
Cauda equina 
Sacral plexus 
Sciatic n. 
Common peroneal n.

62

What is polyneuropathy?

generalised relatively homogeneous process affecting many peripheral nerves with the distal nerves affected most prominently.

63

What is peripheral neuropathy?

Refers to any disorder of the peripheral nervous system including radiculopathies and mononeuropathies

64

List some common causes of length dependent polyneuropathy

– Diabetes
– Alcohol
– B12 def
– Chemotherapy
– Idiopathic

65

List the symptoms of length dependent polyneuropathy

– Numbness, paraesthesia, weakness
– Pain

66

Describe Guillian barre syndrome

Also known as Acute inflammatory demyelinating polyneuropathy 

Immune response to a preceding infection 

Rapidly progressive (days to weeks) weakness
including limbs, facial, respiratory and bulbar muscles 
Absent reflexes

67

Give the site of damage for motor neuropathy

Anterior horn cell

68

Give the causes of motor neuropathy

ALS, Polio

69

Give the site of damage for sensory neuropathy

Doral root ganglion

70

Give the causes of sensory neuropathy

Sjogrens syndrome, Paraneoplastic

71

What does polyradiculopathy affect?

Affects multiple nerve roots

72

What are the causes of polyradiculopathy?

– Spinal stenosis: Cervical, lumbar
– Cancer: Leptomeningeal metastases
– Infection: Lyme, HIV

73

Describe shin splints

Muscle bulk increases 20% during exercise and contributes to the transient increase in intracompartmental pressure

Anterior and lateral compartments of the lower leg are commonly affected Generally causes pain on and post exercise- AKA Shin Splints

Manage with RICE (rest / cooling – ice

74

What is compartment syndrome?

Increase in pressure within a myofascial compartment which has limited ability to expand
May be acute or chronic
Acute compartment syndrome is a surgical emergency

75

Where does compartment syndrome occur?

Any limb compartment Commonest Lower leg Forearm

Also Hand Foot

76

What causes compartment syndrome?

Fractures (1-6% Tibial Fractures)
Crush Injuries
Burns
Electric Shock
Fluid Injection
Drugs • Warfarin/other anticoagulants • Anabolic Steroid use • Iv drug use
Disease • Haemophilia
External Causes • Tight splints/casts • Tourniquet

77

What are the consequences of compartment syndrome?

Tissue perfusion is proportional to the difference between the capillary perfusion pressure and the interstitial fluid pressure

elevated compartment pressure causes muscle and nerve ischemia

Untreated, within 6-10 hours, the final result is muscle infarction, tissue necrosis, and nerve injury

Certain tissues are more sensitive than others and this can be a clue to diagnosis Sensory nerves

78

Describe acute anterior compartment syndrome

Dorsiflexion muscles of ankle and foot Tibialis anterior, Extensor digitorum longus Extensor hallucis longus, Peroneus tertius Anterior tibial artery Commonly injured in lateral tibial plateau fractures Deep peroneal nerve Sensation to the first dorsal web space

79

Describe aute posterior compartment syndrome

uperficial posterior Plantar flexors of foot Gastrocnemius Plantaris Soleus Sural nerve Sensation to lateral aspect of the foot and distal calf

80

What are the signs of compartment syndrome?

Pain! (out of proportion to the original injury)  Pain +++ on passive stretching  Tense limb  Decreased function of the compartment muscles  Distal neurologic compromise  Reduced distal pulses

81

What investigations are carried out in compartment syndrome?

Clinical suspicion is all important

Measuring of intra-compartmental pressures can be useful

Creatine kinase (CK) of 1000-5000 U/mL Myoglobinuria

82

Describe the management of acute compartment syndrome

Genuine confirmed CS is an emergency

Often surgery is required Aim is to lay open the myofascial compartment and diminish intra-compartmental pressure

However don’t forget to look for external causes Tight casts/ splints Dressings

83

What can be some complications of mismanagement of compartment syndrome?

Little or no return of function can be expected
when diagnosis and treatment are delayed
Rhabdomyolysis - Renal Failure
Limb Loss

84

When must the fasciotomy be performed for a good prognosis?

If fasciotomy is performed within 25-30 hours
following onset of acute CS, the prognosis is
good