Lecture 13- Lower Limb Nerve Injuries and Compression syndrome

Question 1

What are the landmarks for lumbar pucnture?

Answer 1

• Needle inserted between L3/L4

- Lying down on the side

Question 2

Describe the pain of cauda equina vs conus medularis?

Answer 2

• Cauda equina: Radicular and more severe

- Conus Medullaris: Less severe

Question 3

Compare the location of the pain for cauda equina and conus medullaris?

Answer 3

• Cauda Equina: unilateral and asyymetric affecting perineum, thighs and legs
• Conus Medullaris: Bilateral, perineum and thighs

Question 4

Describe the sensory disturbances in cauda equina and cona medullaris?

Answer 4

Cauda equina: Saddle, unilateral and asyymetric

Conus Medullaris: Bilateral saddle distribution

Question 5

Describe the motor loss for cauda equina and conus medullaris?

Answer 5

Cauda equina: Asymmetric and atrophy

Conus Medullaris: symmetric

Question 6

Describe how the reflexes are affected in cauda equina and conus medullaris?

Answer 6

Cauda equina: ankle and knee reflex reduced

Conus Medularis: Ankle only reduced

Question 7

Describe when cauda equina and conus medullaris affects the bowel/bladder function?

Answer 7

Cauda equina: Late

Conus Medullaris: Early

Question 8

Describe the effect of cauda equina and conus medullaris on the sexual function?

Answer 8

Cauda equina: Impaired but less severe

Conus Medullaris: Impaired but more severe

Question 9

what are the caused of cuada equina:

Answer 9

Disc herniation, spinal fracture and tumours

Question 10

Describe the causes of Conus medullaris?

Answer 10

Disc herniation and tumour
Also inflammatory condition: 
1) Chronic inflammatory demyelinating 
2) Polyradiculopath
3) Sarcoidosis

Infections:
CMV, HSV, EBV, Lyme and TB

Question 11

Name where cauda equina is likely to occur?

Answer 11

L5/S1- disc herniation

Question 12

name the mechanism in which cuada equina occurs?

Answer 12

• L5/S1 centrel herniation of the nucleus pulpous

- Deformity of the thecal sac impinging on the cuada equina

Question 13

Describe the lower limb dermatomes?

Answer 13

-More variable than the upper limb

Question 14

Which dermatome covers knee jerk and ankle jerk?

Answer 14

Knee jerk- L4

Ankle jerk S1

Question 15

Describe the causes of lumbosacral plexus lesions?

Answer 15

1) child Birth
2) STructural
3) Non-structural

Question 16

Describe how childbirth is a cause of lumbosacral plexus lesion?

Answer 16

Child birth- prolonged labour and large head affecting the obtrutor nerve causing numbness in the inner thigh

Question 17

Describe how structural issues cause lumbosacral plexus lesions?

Answer 17

• Haemotoma (on warfarin)
• Abscess
• Malignancy-infiltration
• Trauma

Question 18

Describe how non-structural issues cause lumbosacral plexus lesions?

Answer 18

• Inflammatory
• Diabetes
• Vasculitis
• Radiotherapy

Question 19

Describe the presentation if the femoral nerve damage is proximal?

Answer 19

Hip flexors and illipsoas are affected if the damage is proximal

Question 20

Describe what would be affected if the damage is below the inguinal ring?

Answer 20

-Only knee extension affected if damage below the ligament

Question 21

Describe what would be affected if the lesions is more distal?

Answer 21

Distal lesions may produce a pure motor or a pure sensory syndrome

Question 22

Describe the nerve root entrapment in sciatica?

Answer 22

Nerve L5/S1 entrapped

Question 23

What can be differential diagnosis where pain is in sciatic nerve distribution?

Answer 23

Hip pain- may radiate- NOT below the knee

Sacroilliac joints

Question 24

What are the possible causes of sciatica type pain?

Answer 24

• Trauma
• Haemotoma
• Rarely sciatic nerve compression per se (pirifformis syndrome)
• Misplaced IM injection

Question 25

Describe why the piriformis syndrome diagnosis may be conterversial?

Answer 25

• Conterversial as to whether muscle compression per se can cause tingling in the buttock and down leg
• E.G. after exercise or straining or prolonged sitting
• May rarely occur in those with anatomical predisposition
• No diagnosis criteria