Flashcards in Lower limb nerve injuries and compression syndromes Deck (84):
Where is the conus medularis?
What is found below the conus medularis?
Where are lumbar punctures taken?
Describe the severity of cauda equina pain
Describe the severity of conus medularis pain
Give the location of the cauda equine pain
Unilateral/asymmetric Perineum, thighs, and legs.
Give the location of conus medularis
Bilateral Perineum, thighs
Describe the sensory disturbance of the cauda equina
Describe the sensory disturbance of the conus medularis
Bilateral saddle distribution
Describe the motor loss of cauda equina
Asymmetric and atrophy
Describe the reflexes of cauda equina
Ankle and knee reduced
Describe the reflexes of conus medularis
Ankle only reduced
Describe the bowel and bladder in cauda equina
Describe the bowel and bladder in conus medularis
Describe sexual function in cauda equina
Impaired - less severe
Describe sexual function in conus medularis
Impaired - more severe
List some causes of cauda equina
List some causes of conus medularis
List some inflammatory conditions which may cause conus medularis
Chronic inflammatory demyelinating
List some infections which may cause conus medularis
Compression- Disc- posterior central, lateral Bone- osteophyte Ligaments Small canal- stenosis
Which nerve roots is sciatica usually?
Where is the L5 nerve root?
Between L5 and S1 vertebral bodies
Where is the S1 nerve root?
Between S1 and S2 vertebral bodies
Where may pain be felt in sciatica?
Myotome (deep ache)
What is the L1 dermatome?
What is the L2 dermatome?
Front of thigh (front pocket)
What is the L3 dermatome?
Front of knee
What is the L4 dermatome?
What is the L5 dermatome?
Outer leg, dorsum of the foot, inner sole
What is the S1 dermatome?
Little toe, rest of sole, back of leg
What is the S2 dermatome?
Thigh to top of buttock (back pocket)
Where are the S3-S5 dermatomes?
Rings around anus and genitalia
Which spinal level is the knee jerk reflex?
Which spinal nerve is the ankle jerk reflex?
Which action does L1/2 do?
Which action does L3/4 do?
Which action does L4 do?
What action does L5 do?
Foot inversion and eversion
What action does S1 do?
Ankle plantar flexion
List the causes of lumbosacral plexus lesions
List some structural causes of lumbosacral plexus lesions
Haematoma (on Warfarin
Malignancy – infiltration
List some non-structural causes of lumbosacral plexus lesions
What would be affected in proximal femoral nerve damage?
Hip flexors, Iliopsoas
What would be affected of a lesion in the femoral nerve below the inguinal ligament
How can the femoral nerve be damaged?
Surgery Gynae procedures, esp hysterectomy, femoral a. bypass/ puncture
What may be the cause of sciatica
Haematoma Rarely sciatic nerve compression per se (Piriformis synd)
misplaced IM injection
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
What can partial sciatic nerve damage look like?
Common peronal or Tibial nerve damage
Where is the tibial nerve located?
Behind the knee
What actions cant be performed after tibial nerve damage?
Can’t stand on tiptoes
Weak foot inversion
Painful numb sole
List some causes of tibial nerve damage
Entrapment by the tendinous arch at the soleus muscle.
Where does the tibial nerve branch?
Name the branches of the tibial nerve
gastrocnemius, popliteus, soleus and plantaris, and the sural nerve.
What passes through the tarsal tunnel?
tibialis posterior, flexor digitorum longus, flexor hallucis longus
Intrinsic foot muscles
Give some symptoms of tarsal tunnel syndrome
Sole pain worse standing/ walking
Not heel pain
What would be a differential for tarsal tunnel?
Differential Morton’s neuroma
How may the common peronal nerve be damaged?
May also be damaged by tight plaster casts, leg crossing, Weight loss- slimmers palsy
Give the sensory loss of damage to the common peronal nerve
dorsum of foot and outer aspect lower leg
What weakness would result from damage to the common peronal nerve?
dorsiflexion and eversion of foot
List the nerves which could be affected in neurogenic foot dropo
Upper motor neuron (brain/ spinal cord)
Common peroneal n.
What is polyneuropathy?
generalised relatively homogeneous process affecting many peripheral nerves with the distal nerves affected most prominently.
What is peripheral neuropathy?
Refers to any disorder of the peripheral nervous system including radiculopathies and mononeuropathies
List some common causes of length dependent polyneuropathy
– B12 def
List the symptoms of length dependent polyneuropathy
– Numbness, paraesthesia, weakness
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
Give the site of damage for motor neuropathy
Anterior horn cell
Give the causes of motor neuropathy
Give the site of damage for sensory neuropathy
Doral root ganglion
Give the causes of sensory neuropathy
Sjogrens syndrome, Paraneoplastic
What does polyradiculopathy affect?
Affects multiple nerve roots
What are the causes of polyradiculopathy?
– Spinal stenosis: Cervical, lumbar
– Cancer: Leptomeningeal metastases
– Infection: Lyme, HIV
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
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
Where does compartment syndrome occur?
Any limb compartment Commonest Lower leg Forearm
Also Hand Foot
What causes compartment syndrome?
Fractures (1-6% Tibial Fractures)
Drugs • Warfarin/other anticoagulants • Anabolic Steroid use • Iv drug use
Disease • Haemophilia
External Causes • Tight splints/casts • Tourniquet
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
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
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
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
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
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
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