5.4 Syndromes of the spinal cord and PNS Flashcards
What nerves are you testing with Biceps jerk Brachioradialis Triceps Finger Knee Ankle
Biceps jerk C5 (6) Brachioradialis C6 Triceps C7 Finger C8 Knee L4 Ankle S1
What are upper and lower motor neurons?
Upper = brain and spinal cord Lower = nerves, nerve roots and plexus
What typically is the difference between UMN and LMN lesions?
UMN: descending inhibition is usually lost so stretch reflexes are overactive
LMN: reflexes will be reduced
What are the signs of UMN lesions?
Spastic weakness, increased tone, pyramidal pattern of weakness, increased reflexes, positive babinski and hoffmans, minimal atrophy
What are the signs of LMN lesions?
Flaccid weakness, decreaed tone, non pyramidal weakness, negative babinski and hoffmans, marked atrophy, fasiculations
What effect does a complete cord lesion have
Everything above fine and below not
What effect does a brown-sequard lesion have?
Affects one half of the spinal cord so pain and temperature will be affected on the opposite side to proprioception and motor
What effect will a central cord lesion have?
Pain and temperature loss
What effect with a posterior cord lesion have?
Loss of proprioception and vibration sense due to damage of the dorsal column pathways
What tracts does an anterior lesion affect?
corticospinal and spinothalamic
What are the causes of cord compression?
Cervical spondylosis
Thoracic disc prolapse
Tumours
Haematoma and abscesses (rare)
What levels does cervical spondylosis commonly occur and why
C4/5 5/6 6/7 due to the increased mobility of the spine at these levels
What happens in cervical spondylosis?
The cord gets stretched over the spondylitic bar in extension, this can cause the ligamentum flavum to be buckled in extension
What is the presentation of cervical spondylosis
Predominantly motor presentation in legs with motor neuron and sensory signs in the arms
When you have cord compression will you have UMN or LMN symptoms?
UMN below the level of the lesion and LMN at the level of the lesion
What is cauda equina syndrome?
Where you have dysfunction of most of the descending nerve roots within the lumbar spinal canal (lesion taking these out)
no UMN signs as this is below the spinal cord
What are the symptoms of cauda equina syndrome?
Saddle sensory loss Distended atonic bladder Constipation, decreased anal/rectal tone, fecal incontinence Loss of erectile function Weakness in sacral mytomes
What are the common causes of cauda equina syndrome?
Central lumbar disc prolapse Epidural metastases Benign tumour Neoplastic meningitis Trauma
What is a radiculopathy?
Nerve root pathology
What are the two common causes of radiculopathy?
Compression at the neural exit foramen
Compression of the descending root within the central canal (lumbar > sacral)
What are the symptoms of a radiculopathy?
Pain and sensory loss in the dermatome
LMN weakness in affected myotome
Back pain, lumbar/cervical muscle spasm, postural changes, intolerance of head movements
How are the nerves named in the spine?
In the neck = named after the vertebrae below
Elsewhere = named after one above
If you have an L5 nerve issue which disc is most likely to be involved?
L4/5
How do you differentiate a common peroneal and L5 lesion?
Peroneal will spare the tibialis posterior and hamstrings
What nerve is affected in carpal tunnel?
Median
What is the typical presentation of carpal tunnel?
Parasthesia or hypothesia in the thumb and adjacent 2.5 digits, sparing sensation over the thenar eminence
What is the motor loss in carpal tunnel?
LOAF muscles
1,2 lumbricals, opponens pollicus, ABP and FBP
What do you get in compression of the ulnar nerve?
Ulna claw - weakness of FDP, all intrinsic muscles apart from median LOAF muscles
- hyperextension at MCP joints and flexion at DIP and PIP on ulna side of hand
Sensory: loss in lateral 1.5 digits and adjacent palm
What nerve is affected in wrist drop?
Radial
