Lower Limb Nerve Injury Flashcards
Sacral roots come out?
T12 to L1
Lumbar puncture happens at?
L3/4
Cauda equina symptoms?
Radicular pain, spreading out electrical
Unilateral pain
Sensory disturbance unilateral
Sexual Function is less impaired
Disc herniation that compressing cauda equina happens at what level?
L5/S1
Knee jerk at which level?
L4
ANkle jerk at which level?
S1
Femoral nerve comes off which level?
L2,3 and 4
Sciatic nerve comes off
L4/5 S 1 2 3
Femoral nerve organisation?
Psoas iliacus before inguinal ligament
Then below, innervation to knee extensors
Lateral cutaneous nerve comes off?
L2/3, below inguinal ligament
Numbness outer lateral thigh will be due to?
Lateral cutaneous nerve damage
Common perineal winds around?
Fibular head
Tibial nerve is responsible for?
Inversion and flexion of everything
Which nerve would you use for nerve biopsy?
Sural nerve
Plexopathy?
When proximal part of limb affected
Differences between cauda equina and conus medullaris?
Conus: Less severe pain, Symmetrical Bilateral Ankle reflex only reduced Bowel/bladder symptoms are early Sexual function impairement is more
What is sciatica caused by?
usually L5, s1 n root impingement
Dermatomes?
L1, inguinal area L2, front of thigh L3 front of knee L4, front - inner medial leg L5, outer leg, dorsum o foot inner sole S1, little toe, rest of sole, back of leg S2, thighs to top of buttock S3-s5 concentric rings around anus, genitalia
Femoral nerve damage can happen due to?
Gynaecological reasons and pelvic fracture
Isolated hip fracture affects what and what does pelvic and sacral fractures affect?
Sciatic nerve
Sacral plexus
What can cause sciatic nerve injury?
Hip dislocation, Acetabular fracture Surgical trauma Injections Radiation Tourniquets Positioning during anaesthesia
If you injure the tibial nerve then you can’t?
Stand on tip toes
Weak foot inversion
Painful numb sole
Tibial nerve gives branches off to?
Gastrocnemius, popliteus, soleus, plantaris and the sural nerve
What are the causes of tibial nerve injury?
Trauma.
Bakers cyst
Nerve tumour
Entrapment by the tendinous arch of the soleus muscle
Sural nerve supplies?
Lateral foot
Common fibular nerve damaged by?
Tight plaster casts, leg crossing, prolonged squatting
Strawberry’s pickers
Slimmers palsy
Common peroneal nerve damage?
Sensory loss in dorsum of foot and outer aspect of leg
Weakness of dorsi flexion and eversion of foot
Length dependent poly neuropathy causes?
Alcohol Vit b12 deficiency Diabetes Idiopathic Chemotherapy
Clinical symptoms of length dependent polyneuropathy?
Numbness
Paraesthesia
Weakness
Pain
Non-length dependent polyneuropathy?
Guillian barre syndrome
Post infection inflammatory condition that picks off peripheral nerves
Antibody injures myelin membranes or axonal
Symptoms of GB syndrome?
Rapidly progressive days to weeks
Weakness including limbs facial respiratory and bulbar muscles
Absent reflexes
Neuronopathy?
Affecting the cell body of the nerve
What is compartment syndrome?
Increases in pressure within a myofascial compartment which has limited ability to expand. This leads to compromised circulation and function of the tissues
Acutely it is a surgical emergency
Commonest site for compartment syndrome?
Leg and forearm
What percent of tibial fractures are associated with compartment syndrome?
1-10%
Signs of compartment syndrome?
Pain on passive movement Tense limb Reduced sensation Muscle weakness paralysis Pallor Reduced pulse
Investigations for compartment syndrome?
CK
Raised lactate
Myoglobinuria
