lower nerve injuries Flashcards
Cauda equina symptoms
- Pain severity
- Location of pain
- Sensory distribution
- Motor loss
- Reflexes
- Bowel/bladder
- Sexual function
Pain severity
- Radiates
- More severe than conus medullaris
Location of pain
- Unilateral
- Asymmetric
- Perineum, thighs, legs
Sensory distribution
- Saddle
- Unilateral/ asymmetric
Motor loss
- Asymmetric
- Atrophy
Reflexes
- Ankle and knee reduced
Bowel/ bladder
- Symptoms present later
Sexual function
- Impairment is less severe than conus medullar is
Cauda equina
- Description
- Causes
Lesion below L1/2
- LMN lesion
Causes
- Disc herniation
- Spinal fracture
- Tumours
Conus medullaris
- Description
- Causes
Lesion at L1/2 cord
Causes
- Disc herniation
- Tumour
- Inflammatory: sarcoidosis, chronic inflammatory demyelinating, polyradiculopathy.
- Infection: CMV, HSV, EBV, Lyme, TB
Conus medullaris symptoms
- Pain severity
- Location of pain
- Sensory distribution
- Motor loss
- Reflexes
- Bowel/bladder
- Sexual function
Pain
- Less severe than caudal equina
Location
- Bilateral
- Perineum, thighs
Sensory
- Bilateral
- Saddle
Motor loss
- Symmetric
Reflexes
- Ankle reduced only
Bowel/bladder
- Presents earlier
Sexual - Severe dysfunction
Sciatic (nerve root compression)
- Nerve roots compressed
- Causes of compression
- Pain
Impingement of level root at L5/S1
Compression can be caused by
- Disc herniation
- Osteophyte
- Ligaments
- Stenosis of spinal canal
Pain
- Sharp in dermatome
- Dull ache in myotome
Dermatomes
- L1-5
- S1-3
L1
- Inguinal area
L2
- Front of thigh
L3
- Front of knee
L4
- Inner leg
L5
- Outer leg, dorsum of door, inner sole
S1
- Little toe, back of leg
S2
- Thigh on top of buttock
S3-5
- Around anus/genitalia
Knee jerk nerve root
L4
Ankle jerk nerve root
S1
Causes of lumbosacral plexus lesions
Childbirth
Structural
- Haematoma/ warfarin
- Abscess
- Infiltration from malignancy
- Trauma
Non-structural
- Inflammatory
- Diabetes
- Vasculitis–> prevents blood supply to nerves
- Radiotherapy
Femoral nerve lesion organisation
If proximal
- Iliopsoas affected= weak hip flexors
Below inguinal ligament
- Only knee extension affected
- Loss of knee jerk
Distal
- Pure motor or sensory syndrome
Causes of femoral nerve damage
Pelvic fracture
Prolonged dorsal lithotomy position
- In surgery
Gynae procedures
- Hysterectomy
Femoral artery bypass/ puncture
Sciatica
- Description
- Causes
- Differentials
- Movements affected
Nerve root entrapment of L5/S1
- Sciatic nerve distribution pain
Causes
- Trauma
- Haematoma
- Piriformis syndrome
- Misplaced IM injection
Differentials
- Osteoarthritis [sacroiliac joints
- Hip problem [if pain more below knee]
Movements affected, everythng but:
- Hip flexion
- Knee extension [Femoral]
- Hip adduction [medial muscles, obturator]
Sciatic nerve
2 compartments
- Common peroneal
- Tibial
Presents differently if nerve is partially damaged
Divisions:
- Sural
- Common peroneal
- Tibial
- Superficial/deep peroneal
- Medial lateral plantar
Tibial nerve damage
Responsible for plantar flexion, inversion
- Damage= cannot tip toe, weak foot inversion, painful numb sole
Causes:
- Trauma
- Baker’s cats
- Nerve cyst
- Tumour
- Entrapment by tendinous arch of soles muscle
Tarsal tunnel syndrome
Compression of tibial nerve in tarsal tunnel
Presents
- Pain in sole, worse on standing/ waling
- No heel pain
Sural nerve
Sensory nerve from tibial and common peroneal nerve
- Posterior to lateral malleolus
Commonly used for nerve biopsy, i.e to diagnose vasculitis.
- Purely sensory
- Supplies little area
Common peroneal nerve damage
From sciatic nerve
Causes - Leg crossing - Tight plaster cast - Weight loss - Fibula fracture Sensory loss - Lower lower leg - Dorsum of foot
Motor loss
- Dorsiflexion
- Eversion of foot
Causes of neurogenic foot drop
UMN lesion
- Tumour
- Stroke
- Polio
Common peroneal lesion
- Most common
L4/5 entrapment
Cauda equina
Conus medullar is
Sciatic nerve lesion
Length dependent polyneuropathy
Lesions in the longest nerves
- usually in the lower limb
Presents - Numbness, paraesthesia, weakness, pain of affected regions Causes - Diabetes - Alcohol - B12 deficiency - Chemotherapy
Guillain Barre syndrome
Acute inflammatory demyleinating polyneuropathy
Antibodies are produced proceeding infection
- Injuries myelin or axon
Presents
- Rapid progression
- Weakness in limbs, face, respiratory and bulbar muscles
- absent reflexes
Neuronopathy
Polyneuropathy that affects specific population of neurones
- motor: anterior horn cell lesion [polio, ALS]
- Sensory: Dorsal root ganglion [Sjogren’s syndrome, paraneoplastic]
Polyradiculopathy
Lesion affecting many nerve roots
Causes
- Spinal stenosis of spinal canal
- Cancer: leptomeningeal metastatsis
- Infection: lyme, HIV
Shin splints
Transient increase in intracompartmeyt pressure in the anterior/ lateral leg= pain on/post exercise
- Due to compression of nerve
Treat with RICE
Compartment syndrome
Increase in pressure within myofascial compartment
= Limits ability for muscle to expand
- Muscle and nerve ischaemia
When acute= surgical emergency
Most common in
- Lower leg
- Forearm
Signs
- Pain very in proportional to injury, increased in passive stretching
- Tense limb
- Decreased function
- Neurologic comprimise distally
- Reduced distal pulses
Causes
- Fractures [esp. tibial]
- Crush injuries
- Burns
- electric shock
- Fluid injection into muscle
- drugs: warfare, anabolic steroids, IV
- Haemophilia
Acute anterior compartment syndrome in leg
- Structures affected (how) and consequences
anterior tibial artery
- Lateral tibial plateau fractures
Deep peroneal nerve
- Loss of sensation in first dorsal web space
Muscles that dorsiflex ankle and foot affected
Acute posterior compartment syndrome in leg
Plantar flexors in foot affected
- Gastroc
- Plantaris
- Soleus
Sural nerbe
- Lateral foot and distal calf sensation affected
